CURRENT ELECTRICITY 1. What are the minimum requirements to cause the flow of current? A. A voltage source, an ammeter, a conductor and an insulator B. A voltage source, a switch and a resistor C. A voltage source and a conductor D. A voltage source, a conductor and an insulator 2. Out of the following, select the best conductor of electricity. A. Graphite B. China clay C. Porcelain D. None of these 3. Which of the following statements is correct? A. The resistance does not play an important role in electrical engineering. B. The resistance of a wire does not depend upon its material. C. The resistance of most of the materials is independent of the temperature. D. The resistance of conductor is the hindrance by which the conductor opposes the flow of the current. 4. Resistance of a conductor increases when A. its length increases B. its area increases C. both length and area increases D. specific resistance is kept constant 5. The specific resistance depends upon A. The area of cross-section and the length of the conductor B. The material of the conductor, its area of cross-section and length C. The nature of the material of the conductor only D. The area of cross-section of the conductor 6. The specific resistance is defined as A. resistance of a conductor which has a length of 1 m and cross-section of 1 m2 at 20oC B. resistance of any conductor at 25oC C. resistance of any conductor at 20oC D. resistance of a conductor which has a length of 1 m and cross-section of 1 cm2 at 20oC 7. The resistance of a conductor, when its temperature is increased A. remains constant B. increases C. varies D. decreases 8. It was experimentally found by James Prescott Joule that the heat produced in a current carrying conductor is proportional to A. the square of the current B. square of resistance C. the current D. inversely proportional to time 9. The value of Joule’s mechanical equivalent of heat, J, is equal to A. 4.2 calories per Joule B. 2.4 Joules per calorie C. 4.2 Joules per calorie D. 4.2 Joules A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 1 of 94 CURRENT ELECTRICITY 10. Temperature coefficient of a conductor is defined as the A. increase in resistance per ohm per degree centigrade B. increase in resistance per degree centigrade C. increase in resistance per degree absolute D. decrease in resistance per ohm per degree centigrade 11. When current flows in a conductor, heat is produced because A. heat α I2 B. of electronic collision C. of interatomic collision D. of Joule’s law 12. Heating effect of current has undesirable side effect in A. electric oven B. electric iron C. immersion heater D. vacuum cleaner 13. The resistance of carbon (filament in carbon-filament lamps) when its temperature is decreased A. increases B. decreases C. remains the same D. increases enormously 14. The curve representing Ohm’s law is A. a parabola B. linear C. sine function D. a hyperbola 15. The condition in Ohm’s law is that A. ratio V/I should be constant B. current should be proportional to voltage C. the temperature should remain constant D. the temperature should vary 16. Ohm’s A. B. C. D. law does not apply to conductors conductors when there is change in temperature semiconductor a.c. circuit 17. Ohm’s law is applicable to A. electric arc C. gas discharge lamps B. rectifying devices D. none of these 18. Ohm’s law can be applied with certain reservations to A. rectifying devices B. semiconductors C. electrolytes D. thermionic valves 19. The presence of an electric current is made known by A. flashing B. effects produced C. cracking D. electric shock 20. An electric current can neither be A. felt, seen C. seen, produced any effect _ nor . B. seen, touched D. produced, felt A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 2 of 94 CURRENT ELECTRICITY 21. The presence of the current is only made known by the effect it produces. Three important effects are A. heating, electric shock and generation B. generation, chemical and electric shock C. heating, magnetic and electric shock D. heating, magnetic and chemical 22. Voltage applied across a circuit, acts as A. mass of electrons C. a component of current B. negative ions D. a force 23. In a series circuit the current is A. constant C. proportional to the resistance B. always zero D. different in different resistors 24. In a parallel circuit the potential difference across the resistance A. varies B. is different from the applied voltage C. is sometimes constant D. is always constant 25. The resistance R1 and R2 are connected in parallel. The ratio of values of resistance R 1 : R2 is 4 : 1. The currents in R1 : R2 will be equal to A. 1 : 4 B. 1 : 1 C. 4 : 1 D. 4 : 4 26. A resistance of 4 ohms is connected across 100 V supply. When another resistor ‘R’ ohms is connected in parallel with 4 ohms, the total current taken from supply was found to be 50 A. The value of resistance ‘R’ is A. 2 ohms B. 3 ohms C. 5 ohms D. 4 ohms 27. The voltage applied across an electric press was reduced by 50%. The power consumed by the press will be reduced by A. 25% B. 75% C. 60% D. 50% 28. Two electric presses are connected in parallel. The resistance of the first press is 100 ohms and that of the second is 300 ohms. The total current taken by both the presses is 4 A. The ratio of current taken by first : second will be equal to A. 2 : 3 B. 1 : 3 C. 3 : 1 D. 1.2 : 3 29. Three elements having conductance G1, G2 and G3 are connected in parallel. Their combined conductance will be 1 A. G1 + G2 + G3 B. G1 G2 G3 1 G1G2 G2 G3 G3G1 D. C. G1 G2 G3 1 1 1 G1 G2 G3 30. Four resistances R1, R2, R3 and R4 are connected in series against 220 V supply. The resistances are such that R1 > R2 > R3 > R4. The least power consumption will be in A. resistor R1 B. resistor R4 C. resistor R3 D. resistor R2 A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 3 of 94 CURRENT ELECTRICITY 31. When current flows through heater coil it glows but supply wiring does not glow because A. supply wiring is covered with insulation layer B. current through supply line flows at slower speed C. supply wires are made of superior material D. resistance of heater coil is more than that of supply wires 32. Resistors commonly used in power circuits are A. carbon resistors C. wire wound resistors B. etched circuit resistors D. deposited metal resistors 33. International ohm is defined in terms of resistance of A. a column of mercury B. a cube of carbon C. unit length of metal wire D. a cube of copper 34. Which of the following has negative coefficient of resistance? A. wire wound resistor B. non-metals C. thermistor D. metals 35. The current carrying capacity of the fuse material depends on A. length B. material C. cross-sectional area D. all of these A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 4 of 94 MAGNETISM AND ELECTROMAGNETISM 1. A natural magnet is called A. steel B. lodestone C. magnetism 2. A magnet is able to attract A. iron, aluminum and brass C. iron, copper and nickel B. iron, cobalt and zinc D. nickel, cobalt and steel 3. Externally, magnetic line of force travels A. south to north C. negative to positive B. north to south D. in both directions 4. A material commonly used for shielding or screening magnetism is A. brass B. aluminum C. copper D. soft iron D. soft iron 5. The magnetism that remains in a magnet after the magnetizing force has been removed is called A. permeability B. induction C. residual D. saturation 6. Iron becomes magnetized by induction when it is A. heated B. suspended east and west C. near to one end of a magnet D. treated with some chemicals 7. Magnetic lines of force are called A. hysteresis B. current C. flux D. magnetomotive force 8. The force between two magnetic poles varies with distance between them. The variation is A. in direct proportion to the distance B. in inverse proportion to the distance C. in direct proportion to the square of the distance D. in inverse proportion to the square of the distance 9. The magnetic potential in a magnetic circuit can be measured in terms of A. farads B. M.M.F. C. coulombs D. none of these 10. Permeance is analogous to A. conductance B. resistance C. reluctance D. none of these 11. The permeability of a material means A. strength of permanent magnet B. strength of an electromagnet C. the magnetization left in the iron after exciting field has been removed D. the conductivity of a material for magnetic lines of force 12. When the magnetic flux () and the area (A) under its influence are known, the magnetic flux density (B) can be given as B. B A. B A A A C. B D. B A 2 A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 5 of 94 MAGNETISM AND ELECTROMAGNETISM 13. The relative permeability r is given by A. B μ 0H 0 C. B. D. B H 0 H 14. Relative permeability of a material is given by (K is susceptibility of the material) K B. 1 A. 1 0K μ0 C. 1 0 C. 0H K 15. The relative permeability of paramagnetic substance is A. slightly less than 1 B. equal to 1 C. slightly greater than 1 D. very much greater than 1 16. The value of permeability for the free space is A. 4 x 10–7 Hm–1 C. 4 x 107 Hm–1 B. 4 x 10–7 Hm–1 1 10 7 Hm1 D. 4 17. The magnetization in any magnetic material appears as a result of A. electrons orbital motion B. electron spin C. spin of the nucleus about its axis D. all of these 18. The sum of the magnetic moments in unit volume of the solid is called A. field strength B. magnetization C. permeability D. susceptibility 19. Which of the following materials does not have permanent magnetic dipole A. paramagnetic B. antiferromagnetic C. diamagnetic D. ferrimagnetic 20. Interaction between the neighboring dipoles is negligible in case of a A. paramagnetic material B. diamagnetic material C. antiferromagnetic material D. ferrimagnetic material 21. Each ferromagnetic material has characteristic temperature above which its properties are quite different from those below that temperature. This temperature is called A. transition temperature B. Faraday’s temperature C. demagnetization temperature D. Curie temperature 22. The relative permeability for iron is A. 5000 B. 7000 C. 3000 23. Which of the following material is used for making permanent magnets A. carbon steel B. platinum cobalt C. Alnico V D. 1000 D. All of these A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 6 of 94 MAGNETISM AND ELECTROMAGNETISM 24. Which of the following has the highest value of relative permeability r? A. iron B. supermalloy C. Mu-metal D. 4% Si – Fe 25. Ferrimagnetic materials generally behave as a A. semiconductor C. insulator B. conductor D. any of A, B, or C 26. Transformer cores operating at microwave frequency ranges are generally made up of A. ferrites B. silicon steel C. supermalloy D. alnico V 27. The magnetic materials which can be easily magnetized in both directions are known as A. soft magnetic materials B. hard magnetic materials C. low hysteresis loss materials D. high hysteresis loss materials 28. Eddy current loss can be minimized by A. decreasing the resistance of magnetic medium B. increasing the resistance of magnetic medium C. decreasing the permeability of magnetic medium D. none of the above A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 7 of 94 ELECTROMAGNETIC INDUCTION 1. The coefficient of self-inductance of a coil is defined as B. N/I A. NI / C. / NI D. I / N 2. Which of the following statement is incorrect? A. Whenever the flux linking with the coil or circuit changes the emf is produced. B. The direction of dynamically induced emf can be determined by Flemming’s right hand rule. C. Coefficient of coupling for tightly coupled coil is zero. D. The coefficient of self-inductance is proportional to the square of number of turns on it. 3. Which of the following statements about inductance of a coil is true? A. Inductance is a characteristic of coil occurring only in case of A.C. B. Inductance appears only if the coil has an iron core. C. Inductance is only another expression for self-induced voltage. D. Inductance characterizes the magnetic properties of a coil which are significant for the value of self-induced voltage generated due to current change in the coil. 4. A collapsing field around a coil A. tends to oppose the decay of coil current B. helps the decay of coil current C. tends to aid current flow reversal D. does not affect the coil current flow 5. Energy stored in an inductance is given by A. 2LI 2 joules N C. joules I 6. Which of the following is a vector quantity? A. magnetic potential C. magnetic field intensity B. 0 joule 1 2 D. LI joules 2 B. flux density D. relative permeability 7. A conductor of length L has current I passing through it, when it is placed parallel to a strong magnetic field. The force experienced by the conductor will be A. BLI B. zero C. B2LI D. BL2I 8. Whenever a conductor cuts magnetic flux, an emf is induced in that conductor. This statement is due to A. Joule’s law B. Coulomb’s law C. Faraday’s law D. Weber and Ewing’s theory 9. The left hand rule correlates A. self induction, mutual induction and direction of force on a conductor B. magnetic field, electric field and direction of force on a conductor C. current, induced emf and direction of force on a conductor D. current, magnetic field and direction of force on a conductor 10. In the left hand rule, thumb always represents A. voltage C. direction of force on conductor B. current D. magnetic field A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 8 of 94 ELECTROMAGNETIC INDUCTION 11. The coefficient of coupling between two air core coils depends on A. self inductance of the two coils only B. mutual inductance between the two coils only C. mutual inductance and self inductance of the two coils D. none of the above 12. While comparing magnetic and electric circuits, the flux of magnetic circuit is compared with which parameter of electric circuit? A. e.m.f. B. current density C. conductivity D. current 13. While comparing magnetic and electric circuits, the point of dissimilarity exists while considering A. flux and current flow B. permeance and conductance C. m.m.f. and e.m.f. D. reluctance and resistance 14. The effect of the inductance of a coil on a constant direct current is that A. it strengthens the current B. it does not affect the constant direct current C. it decreases the current D. it causes a higher voltage drop 15. Good smoothing factor of a coil depends on the A. terminal voltage B. property of the wire of the coil C. inductance of the coil D. cross-sectional area of the wire of the coil 16. Leakage factor is A. less than unity C. more than unity B. equal to unity D. zero 17. The law that induces emf and current always opposes the cause producing them was discovered by A. Lenz B. Faraday C. Maxwell D. Ohm 18. According to Lenz’s law the direction of induced e.m.f. and hence current A. may be found by the right hand rule B. always opposes the cause producing it C. is determined by the rate of cutting flux D. may be found by the left hand rule 19. Sparking occurs when a load is switched off because the circuit has high A. capacitance B. inductance C. resistance D. impedance 20. The flux linked with a coil of inductance L carrying current i is A. True B. False C. Partly true d dt (Li ) D. Partly false 21. When steel toroidal ring is magnetized by passing current through its coil, it develops no magnetic poles A. True B. False C. Partly true D. Partly false A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 9 of 94 ELECTROMAGNETIC INDUCTION 22. Air gap in the iron core of an inductor prevents A. hysteresis loss B. flux change C. transformer action D. core saturation 23. The growth of current in an inductive circuit follows A. hyperbolic law B. Ohm’s law C. exponential law D. linear law 24. The time constant of an inductive circuit is defined as the ratio of A. R/L B. Rt/L C. Lt/R D. L/R 25. The time constant is the time it takes the current in an inductive circuit to rise to A. 66% of its final steady state value B. 70% of its final steady state value C. 63% of its final steady state value D. 50% of its final steady state value 26. Mutual inductance can also be defined as: d A. M N 2 dt di C. M N 2 dt B. MN D. M N dt 2 di dt 2 d 27. The mutual inductance of two coils is maximum when the coils are A. inclined at an angle of 45 degrees B. at right angle to each other C. facing each other D. touching each other 28. The value of mutual inductance in terms of self inductance of the two coils L1 and L2 is proportional to L1 B. A. L1L 2 L2 C. D. L1 L2 L1L2 29. Coupling coefficient k, a term much used in radio work can be obtained from A. K M L1L2 B. K M L1 / L 2 C. K M/ L1L 2 D. K ML1L 2 30. The coupling coefficient denotes A. the degree of magnetic linkage B. whether the reluctance remains constant C. the variation of inductance between the two coils D. whether the flux linkage is constant 31. It is difficult to magnetize steel because of its A. low permeability C. high permeability B. high retentivity D. high density A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 10 of 94 ELECTROMAGNETIC INDUCTION 32. In electrical machines, laminated cores are used with a view of reducing A. eddy current loss B. copper loss C. hysteresis loss D. windage loss 33. The area of hysteresis loop represents hysteresis loss in A. J/m3/s B. J/cycle C. J/s D. J/m3 34. According to Hysteresis law, hysteresis loss in a material is proportional to A. B1.2 B. B1.6 C. B0.6 D. B3.6 35. A degaussing is the process of A. removing gases from materials B. removal of magnetic impurities C. demagnetizing metallic part D. magnetizing nonmetallic part 36. Hysteresis losses can be reduced by A. using grain-oriented silicon steel B. increasing the frequency of the field C. laminating the core D. none of these A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 11 of 94 ELECTROSTATICS 1. Absolute permittivity of vacuum is taken as A. 8.854 x 10–6 farad/meter B. 8.854 x 10–12 farad/meter C. 8.854 x 10–9 farad/meter D. 8.854 x 1012 farad/meter 2. Relative permittivity of vacuum is A. zero C. unity B. 8.854 x 10–6 farad/meter D. 9 x 109 farad/meter 3. In the electric field, the potential is the work done in joules A. to bring positive charge of one coulomb from infinity to that point B. to bring any charge from infinity to that point C. in moving a unit positive charge from one point to the other point D. to bring any charge from any point to infinity 4. The unit of field intensity is A. coulomb C. newtons/coulomb B. coulomb/m2 D. newtons/m2 5. Coulomb’s law for the force between electric charges most closely resembles with A. Gauss theorem B. Newton’s law of gravitation C. Law of conservation of energy D. Newton’s laws of motion 6. Which of the following equations is correct? A. C. B. Ed l 0 Ed s q 0 D. Ed s q Ed l 0 ss 7. The field F yi x j is a A. rotational field C. conservative field B. irrotational field D. static electric field 8. Dielectric strength of a material depends on A. moisture content C. temperature B. thickness D. all of these 9. What will happen to an insulating medium if voltage more than the breakdown voltage is applied? A. it will get punctured B. it will become magnetic C. it will melt D. its molecular structure will change 10. Which medium has the highest value of dielectric strength? A. glass B. mica C. porcelain D. quartz 11. The maximum value of potential gradient in a cable occurs in A. outer sheath B. insulation B. conductor D. uniformly all over A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 12 of 94 ELECTROSTATICS 12. A region around a stationary electric charge has A. electric field B. magnetic field C. both electric and magnetic field D. neither of the two 13. Inside a hollow spherical conductor A. electric field is constant B. electric field is zero C. electric field changes with distance from the center of the sphere D. electric field is unity 14. Capacitors are said to A. block a.c. and pass d.c. C. pass a.c. and d.c. B. block d.c. and pass a.c. D. block a.c. and d.c. 15. Which statement influences the capacity of a capacitor? A. area of the plates, thickness of the plates and the rate of charge B. area of the plates, dielectric and the rate of charge C. distance between the plates, dielectric and thickness of the plates D. distance between the plates, area of the plates and dielectric 16. The effect of the dielectric is to A. increase the capacitance C. reduce the working voltage B. decrease the capacitance D. increase the distance between the plates 17. Electrolytic capacitor is the most commonly used type but it has two disadvantages, namely A. low insulation resistance and suitable for d.c. only B. high insulation resistance and suitable for a.c. only C. high capacitance and high insulation resistance D. high capacitance and low insulation resistance 18. In a radio, a gang condenser is a type of A. air capacitor B. paper capacitor C. ceramic capacitor 19. A sphere of one meter radius can attain a maximum potential of A. 1000 V B. 3 million volts C. 30 kV D. electrolytic capacitor D. 3 kV 20. The power dissipated in a pure capacitor is A. maximum C. zero B. minimum D. depends on the size and voltage 21. One farad is A. coulomb–joule C. joule per volt B. one coulomb per volt D. one volt per coulomb 22. If a dielectric is placed in a electric field, the field strength A. decreases B. increases C. remains the same D. becomes zero A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 13 of 94 ELECTROSTATICS 23. If the medium of a parallel-plate capacitor consists of mica and air, the capacitance is increased by A. increasing the air space B. increasing the area of the plates C. decreasing the area of the plates D. increasing the thickness of mica 24. A capacitance C is charged through a resistance R. The time constant of the charging circuit is given by 1 C R C. D. A. RC B. RC R C 25. A circuit component that opposes the change in the circuit voltage is A. resistance B. inductance C. capacitance 26. In a capacitor, the electric charge is stored in A. metal plates C. dielectric as well as metal plates D. none of these B. dielectric D. neither dielectric nor metal plates 27. Internal heating of a capacitor is usually attributed to A. leakage resistance B. electron movement C. plate vibration D. dielectric charge 28. The ohmmeter reading for a shorted capacitor is A. infinity B. few kilo ohms C. few mega ohms D. zero A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 14 of 94 ELECTROLYSIS AND STORAGE BATTERIES 1. Electrochemical equivalent is A. ratio of atomic weight of an element to atomic weight of hydrogen B. mass of the element liberated per unit quantity of hydrogen C. ratio of atomic weight of valency D. none of the above 2. The mass of material deposited over an electrode is A. proportional to voltage B. proportional to time only C. proportional to current only D. proportional to quantity of electricity and electrochemical equivalent 3. The mass of an ion liberated at an electrode is directly proportional to the quantity of electricity which passes through the electrolyte. The above statement is associated with A. Gauss’s theorem B. Laplace law C. Weber and Ewing’s theory D. laws of electrolysis 4. In electroplating, the positive electrode is called the A. cathode B. anode C. terminal D. iontrap 5. Impurities in an electrolyte can cause an internal short circuit condition called A. depolarization B. electrolysis C. local action D. polarization 6. Distilled or approved water is used in electrolytes because it A. prevents or slows down local action B. speeds up electrochemical action C. improves specific gravity D. prevents polarization 7. The condition of a liquid electrolyte is measured in terms of its A. current value B. specific gravity C. acid content D. voltage output 8. One factor affecting voltages of the primary cell is the A. area of the plates B. distance between the plates C. types of plates and electrolyte D. thickness of the plates 9. Local action in the primary cell can be rectified by A. charging the cell B. amalgamating the zinc electrode with mercury C. using the cell for just few minutes D. dry cell 10. The action of a dry cell is to change A. chemical action to mechanical energy B. chemical action to electrical energy C. electrical energy into mechanical energy D. electrical energy into magnetic energy 11. Polarization in dry cell can be got rid of by A. coating the electrodes of the cell C. discharging the cell B. chemical means D. disposing the cell A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 15 of 94 ELECTROLYSIS AND STORAGE BATTERIES 12. The two main defects of the primary cell are A. polarization and sulphation C. buckling and polarization B. local action and polarization D. sulphation and buckling 13. The average dry cell gives an approximate voltage of A. 1.3 V B. 1.5 V C. 1.1 V D. 1.7 V 14. To obtain a high voltage of about 1.9 V from a dry cell, one would use A. Western standard cell B. Leclanche cell C. Nickel cadmium cell D. Magnesium cell 15. When n cells, each of emf E volts, and internal resistance r ohms are connected in series, the current i through an external resistance R ohms is given by E E A. i B. i r R n R n nE E C. i D. i R nr r nR 16. When n cells, each of emf E volts, and internal resistance r ohms are connected in parallel, the strength of the current i is given by A. E nE B. r r R R n E E C. D. n Rr n R r 17. Cells are connected in parallel to A. increase the internal resistance C. increase the current capacity B. decrease the current capacity D. increase the voltage output 18. Cells are connected in series to A. decrease the voltage output C. decrease the internal resistance B. increase the voltage output D. increase the current capacity 19. The function of the depolarizer in carbon zinc cell is that A. it converts the produced hydrogen into water B. it prevents the fast chemical action on the zinc container C. it synthesizes the decomposed electrolyte D. it absorbs the oxygen produced in the cell 20. Which of the following acts as depolarizer in dry cell? A. manganese dioxide B. zinc chloride C. ammonium chloride D. carbon powder 21. One advantage of a secondary cell is that it A. can be recharged C. it is compact, easy to carry B. can be used for portable equipment D. cannot be recharged A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 16 of 94 ELECTROLYSIS AND STORAGE BATTERIES 22. The composition of a secondary cell is A. zinc, copper and dilute sulphuric acid B. zinc, carbon and dilute sulphuric acid C. lead, lead peroxide and dilute sulphuric acid D. zinc, copper and dilute boric acid 23. Nickel-cadmium dry cell is becoming popular in power supplies to electronic calculators because A. it has a standard shape B. it is dry C. it is rechargeable D. it is easily manufactured 24. Secondary cell can produce large amounts of power for a A. short time and can be recharged B. long time and can be recharged C. short time and cannot be recharged D. long time and cannot be recharged 25. Gassing occurs in the process of A. charging an accumulator C. discharging an accumulator B. charging a dry cell D. discharging a dry cell 26. The condition of a secondary cell can be determined by A. its terminal voltage B. the color of the electrolyte C. the level of the electrolyte D. the terminal voltage and strength of the electrolyte 27. The lead acid accumulator should be recharged when the specific gravity of the electrolyte is about A. 1.15 B. 1.80 C. 1.25 D. 1.35 28. Other types of accumulators besides the lead acid type are A. alkaline batteries only B. alkaline and solar batteries C. alkaline and dry batteries D. nickel-cadmium batteries 29. Electrolyte of a storage battery is formed by adding A. water to hydrochloric acid B. sulphuric acid to water C. hydrochloric acid to water D. water to sulphuric acid 30. When the electrolyte of a storage battery is low it is usually proper to A. add a special weak acid solution B. top up with distilled water C. charge the battery for a short time before adding an electrolyte D. drain the battery completely and fill it with fresh electrolyte 31. The ampere hour capacity of battery depends on A. the thickness of the plates B. the area of the plates C. the strength of the electrolytes D. the distance between the plates 32. To keep the terminals of a lead acid storage battery free from corrosion, it is advisable to A. clean the terminals frequently B. charge for battery at frequent intervals C. keep the electrolyte level low D. apply petroleum jelly A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 17 of 94 ELECTROLYSIS AND STORAGE BATTERIES 33. The internal resistance of a discharged battery compared with a charged one A. is more B. is less C. remains the same D. is negative 34. It is not desirable to leave a lead storage battery in a discharged state for a long time mainly because A. electrolyte will attack the container B. plates will become sulphated C. electrolyte will become weak D. acid will evaporate 35. A partially discharged lead storage battery may be brought back to full charge by A. adding sulphuric acid B. adding distilled water C. applying ac voltage across the terminals D. applying dc voltage across the terminals 36. Which of the following is a primary cell A. mercury oxide C. nickel-iron-alkaline B. lead-acid D. nickel-cadmium-alkaline 37. Charging a lead-acid cell causes the electrolyte to become A. stronger B. stable C. weaker D. water 38. Separators in storage battery cell are designed to prevent the plates from A. touching the electrolyte B. touching the container C. shorting together D. shorting to the sediment 39. Which of the following affects the capacity of a lead-acid battery? A. temperature B. discharge time C. specific gravity D. all of these 40. During the charging period of a lead-acid battery, the charging rate is lowered to prevent violent gassing because A. the gasses given off are explosive B. evaporation of the electrolyte will weaken its effect C. the cells will be subjected to excessive pressure D. violent gassing tends to wash the active material from the plates 41. A fuel cell converts A. mechanical _ energy into electrical energy. B. magnetic C. chemical D. solar 42. A cell which is used as voltage reference source for instrument calibration is A. solar cell B. dry cell C. mercury-cadmium cell D. nickel-cadmium cell 43. The advantage of the iron-nickel battery over the lead-acid battery is that A. it has a much higher efficiency B. it needs less maintenance C. the cell voltage of the iron-nickel battery is higher D. it is much cheaper 44. While charging accumulators, one should A. check the acid level with a lighted match B. short the cells to see if they are full charged C. keep them in a well-ventilated space D. connect and disconnect them with the supply on A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 18 of 94 D.C. GENERATORS 1. The output voltage of a single loop generator is a A. steady d.c. B. steady a.c. C. pulsating a.c. D. pulsating d.c. 2. A smooth output from a generator is obtained by A. design of the armature winding B. changing the form of the commutator C. changing the field strength D. design of the commutator 3. The output voltage of a generator is given by the equation A. E V IaR a B. E V IaR a C. E L di D. E N d dt dt 4. What effect on current flow does reversing the direction of movement of a conductor in the magnetic field of a generator have A. neutralizes the current flow B. has no effect on current C. it reverses the direction of current flow D. has no effect on the voltage 5. In most generators the output voltage is induced by A. rotating magnetic field past stationary coils B. relative motion between the field and the armature coils C. converting electrical energy into mechanical energy D. converting chemical energy into electrical energy 6. How would you determine, from visual observation of the armature winding, whether a generator is lap or wave wound A. connection to the field winding B. connection to the commutator C. connection to the brushes D. the direction of the end connection 7. What classification is given to a d.c. generator that receives its field excitation current from internal source? A. self excited B. controlled excitation C. separately excited D. internally excited 8. The shunt field of a compound generator is connected across both the series field and the armature. This connection is known as A. short shunt B. long shunt C. differential compound D. cumulative compound 9. For all symbols having their usual meaning, the emf generated in the lap winding is given by LN P ZNA A. E B. E 60 2 2P P φ ZN D. A C. E ZN E 60 A 120 P A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 19 of 94 D.C. GENERATORS 10. Residual magnetism is necessary in a A. separately excited generator C. both of these B. self excited generator D. none of these 11. If the number of poles in a lap wounded generator is increased by a factor of 2, the generated emf will A. remain the same B. increase by a factor of 2 C. decrease by a factor of 2 D. increase by a factor of 4 12. Electric dc generators have normally, an overall efficiency of the order of A. 60-80% B. 75-85% C. 80-90% D. 85-95% 13. The armature magnetic field has effect that A. it demagnetizes or weakens the main flux B. it cross magnetizes, or distorts it C. it magnetizes or strengthens the main flux D. A and B 14. Brushes are always placed along A. magnetic neutral axis (MNA) C. perpendicular to MNA B. geometric neutral axis (GNA) D. perpendicular to GNA 15. Magnetic neutral axis makes an angle of A. 0o B. 90o with the flux passing through the armature. C. 45o D. 180o 16. In a dc generator, the flux is seen to be leading pole tips. A. weakened, weakened C. crowded, weakened at the trailing pole tips and also at the B. weakened, crowded D. same, same 17. If Өm is the forward lead angle in radians, Z is the total number of conductors and I is the current in each armature pole, the demagnetizing ampere-turns/pole are given as θm A. AT ZI m B. ATa ZI a 180 2π 1 2m D. none of these C. ATa ZI P 3 18. The function of a compensating winding is to neutralize the A. reactance voltage generated as a consequence of commutation B. cross magnetize the effect of armature reaction C. demagnetizing effect of armature reaction D. all of these 19. In the commutation process it is the A. current which is getting reversed B. voltage which is getting reversed C. both of these D. none of these A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 20 of 94 D.C. GENERATORS 20. In any dc generator the emf generated in the armature is maximum when A. rate of change of flux linked is minimum B. rate of change of flux is maximum C. flux linked with conductor is maximum D. flux linked with conductor is minimum 21. A simple method of increasing the voltage of a dc generator is A. to decrease the air gap flux density B. to increase the speed of rotation C. to decrease the speed of rotation D. to increase the length of the armature 22. The method which can be used to improve commutation process is A. increasing the resistance of the brushes B. reducing the number of turns in the armature coil and hence the number of segments in the commutator C. to neutralize the reactance voltage by producing a reverse emf in the short circuit coil under commutation D. all of the above 23. The function of interpole or compole is A. to neutralize the reactance voltage and help in commutation process B. to neutralize the cross-magnetizing effect of armature reaction C. to neutralize the demagnetizing effect of the armature D. A and B 24. Interpoles are connected in with the armature and compensating windings are connected in with the armature. A. series, series B. series, shunt C. shunt, series D. shunt, shunt 25. The function of an equalizer ring is A. to avoid unequal distribution of current at the brushes B. to help to get sparkless commutation C. both of these D. none of these 26. Generators are often preferred to be run in parallel because of having the advantages of A. great reliability B. generator efficiency C. meeting greater load demand D. all of the above 27. Which of the following is most suitable for running in parallel operation? A. shunt generator B. series generator C. compound generator D. all of these are equally suitable 28. Critical resistance of a dc generator Rc A. Rc α (speed)–1 C. Rc α (speed)2 B. Rc α (speed) D. Rc α (speed)–2 29. Shunt generators are used where the main requirement is a constant A. current and voltage B. current C. voltage over a wide load range D. voltage over a narrow load range A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 21 of 94 D.C. GENERATORS 30. Equalizer connections are required when paralleling two A. compound generators B. series generators C. shunt generators C. long shunt generators 31. The function of an interpole is A. neutralize cross-field of armature reaction and obtain ideal commutation B. increase the armature reaction and thus obtain ideal commutation C. neutralize cross field of the armature reaction and thus obtain under commutation D. increase the armature reaction and thus obtain over commutation 32. Interpoles are normally connected in A. parallel with field C. parallel with the load B. series with the field D. series with the load 33. In DC generators, lap winding is used for A. low voltage, low current C. low voltage, high current B. high voltage, high current D. high voltage, low current 34. DC generators preferred for charging automobile batteries is A. shunt generator B. series generator C. long shunt compound generator D. short shunt generator 35. Which of the following component of a dc generator plays vital role for providing direct current of a dc generator? A. dummy coils B. equalizer rings C. eye bolt D. commutator 36. In dc generator the ripples in the direct emf and generated are reduced by A. using equalizer rings B. using commutator with large number of segments C. using carbon brushes of superior quality D. using carbon brushes of excellent quality 37. Which of the following generators are preferred for parallel operations? A. series generator B. shunt generator C. compound generator D. all of the above 38. Full load efficiency of the generator will be A. 68.5% B. 73.5% C. 80.8% D. 92.51% 39. Which loss in dc generator varies with load A. copper loss B. eddy current loss C. hysteresis loss D. windage loss 40. In dc generator, the cause of rapid brush wear may be A. imperfect contact B. sever sparking C. rough commutator surface D. any of the above 41. In a shunt generator, the voltage built up generally restricted by A. speed limitation B. armature heating C. saturation of iron D. brush wear A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 22 of 94 D.C. GENERATORS 42. The armature of a dc generator is laminated to A. reduce the bulk B. insulate the core C. reduce eddy current loss D. provide passage for cooling air 43. Which of the following helps in reducing the effect of armature reaction in dc generator? A. compensating windings B. interpoles C. both A and B D. neither A nor B 44. With dc generator, which of the following regulation is preferred A. 1% regulation B. 50% regulation C. infinite regulation D. 100% regulation A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 23 of 94 D.C. MOTORS 1. What is A. B. C. D. the effect produced by the electric motor? magnetic effect only magnetic as well as heating effect heating effect only heating as well as chemical effect 2. The rotating part of a dc motor is know as A. pole B. stator C. armature D. carbon brush 3. The function of the commutator in a dc machine is A. to change alternating current to direct current B. to improve commutation C. for easy speed control D. to change alternating voltage to direct voltage 4. Carbon brushes are used in electric motors to A. brush off carbon deposits on the commutator B. provide a path for flow of current C. prevent overheating of armature windings D. prevent sparking during commutation 5. Voltage equation for dc motor is A. V = Eb + IaRa B. V = Eb – IaRa C. Eb = V + IaRa D. Eb = V – IaRa 6. Condition for maximum power output for a dc motor is A. Eb = V B. Eb = V/2 C. Eb = IaRa D. Eb = 1 2 IaRa 7. The speed of a dc motor is A. directly proportional to back emf and inversely proportional to flux B. inversely proportional to back emf and directly proportional to flux C. directly proportional to emf as well as flux D. inversely proportional to emf as well as flux 8. The highest speed attained by a dc shunt motor is A. equal to infinity of rated flux B. higher than no load speed at rated flux C. equal to no load speed at rated flux D. lower than no load speed at rated flux 9. In a dc motor iron losses occur in A. the yoke B. the armature C. the field D. none of these 10. The dummy coil in dc machines is used to A. eliminate reactance voltage B. eliminate armature reaction C. bring about mechanical balance of armature D. eliminate harmonics developed in the machine A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 24 of 94 D.C. MOTORS 11. An external resistance is added in the series with the field of a dc shunt motor. When the motor runs, the effect of resistance is A. to reduce the speed of the motor B. to increase the speed of the motor C. to reduce the armature current drawn by the motor D. to reduce the losses 12. The speed of a dc shunt motor is required to be more than F.L. speed. This is possible by A. increasing the armature B. decreasing the armature current C. increasing the excitation current D. reducing the field current 13. If speed of a dc shunt motor increases, the back emf A. increases B. decreases C. remains constant D. decreases and then increases 14. The current flowing in the conductors of a dc motor is A. ac B. dc C. ac as well as dc D. transients 15. As the load is increased the speed of a dc shunt motor will A. remain constant B. increase proportionately C. increase slightly D. reduce slightly 16. The current drawn by armature of a dc motor is Eb V A. B. C. Ra Ra V Eb Ra D. Eb V Ra 17. If the current in the armature of a dc series motor is reduced to 5%, the torque of the motor will become A. 50% of the previous value B. 25% of the previous value C. 150% of the previous value D. 125% of the previous value 18. The shunt current flowing in short shunt compound-wound motor is given by I R B. V IscRsc V C. Ish V sc sc Ish A. Ish D. none of these Rsh R sh R sh 19. In dc shunt motor, if the terminal voltage is reduced to half and torque remains the same, then A. speed will be half and armature current also will be half B. speed will be half and armature current remains the same C. speed will be half and armature current becomes double D. speed and armature current will remain the same 20. One dc motor drives another dc motor. The second dc motor when excited and driven A. runs B. does not run as a generator D. runs as a generator D. also runs as a motor A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 25 of 94 D.C. MOTORS 21. Armature torque of a dc motor is given by P A. T 0.159ZI a A kg-m Eb C. T 0.159 I N-m a N B. D. P T 0.1620 / 2I a A N-m P T kg-m A 22. The torque of a motor is A. the force in N-m acting on the rotor B. the product of tangential force on the rotor and its radius C. the electrical power in kW D. the power given to load being driven by the motor 23. The armature current drawn by any dc motor is proportional to A. the voltage applied to the motor B. the torque required C. the flux required in the motor D. the speed of the motor 24. The output power of any electrical motor is taken from A. the armature B. the coupling mounted on the shaft C. the conductors D. the poles 25. The power stated on the name plate of any motor is always A. the output power of the shaft B. the power drawn in kVA C. the power drawn in kW D. the gross power 26. A starter is necessary to start a dc motor because A. it starts the motor B. it limits the speed of the motor C. it limits the back emf to a safe value D. it limits the starting current to safe value 27. The efficiency of any electrical machine/apparatus will be high, if A. its losses are minimum B. its losses are more C. voltage applied is constant D. the current drawn is minimum 28. The direction of rotation of a dc motor is reversed by A. reversing armature connections B. interchanging the armature and field connection C. adding resistance to the field circuit D. reversing supply connection 29. The armature of dc motor is laminated A. to reduce the hysteresis losses C. to reduce the inductivity of armature B. to reduce the eddy current losses D. to reduce the mass of the armature 30. Which of the following is a correct statement about a series motor? A. its field winding consists of thicker wire and less turns B. it can run easily without a load C. it has an almost constant speed D. it has a poor torque A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 26 of 94 D.C. MOTORS 31. Which of the following dc motors has the least drop in speed between no load and nominal load? A. shunt motor with commutating poles B. series motor without commutating poles C. compound motor without commutating poles D. series motor with commutating poles 32. The speed of a series motor at no load is A. zero B. 3000 rpm C. 3600 rpm D. infinity 33. The speed of dc series motor decreases if the flux in the field winding A. remains constant B. increases C. decreases D. none of these 34. Which of the following motors is used to derive the constant speed line shafting lathes, blowers and fans? A. DC shunt motor B. DC sreis motor C. cumulative compound motor D. differential compound motor 35. If the back emf in a dc motor is absent, then A. motor will run at very high speed C. motor will not run at all B. motor will run at very low speed D. motor will burn 36. The field flux of a dc motor can be controlled to achieve A. the speeds lower than rated speed B. the speeds higher than rated speed C. the speeds at rated speed D. none of these 37. By providing a variable resistance across the series field (diverter) in a dc series motor, speeds above normal can be obtained because A. armature current decreases B. flux is reduced C. line current decreased D. none of these 38. DC series motors are best suited for traction work because A. torque is proportional to the square of armature current and speed is inversely proportional to torque. B. torque is proportional to the square of armature current and speed is proportional to torque. C. torque and speed is proportional to the square of armature current. D. none of these 39. A series motor is started without load. The effect is that A. the torque increases rapidly B. the speed increase rapidly C. the current drawn increases rapidly D. the back emf decreases 40. The direction of rotation of a dc series motor can be reversed by interchanging A. the supply terminals only B. the field terminals only C. the supply as well as field terminals D. none of these 41. The motor used for intermittent, high torque is A. dc shunt motor C. differential compound motor B. dc series motor D. cumulative compound motor A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 27 of 94 D.C. MOTORS 42. If the field of a dc shunt motor is opened A. it will continue to run at its rated speed B. the speed of the motor will become very high C. the motor will stop D. the speed of the motor will decrease 43. Which of the following motors is used for rolling mills? A. DC shunt motor B. DC cumulative compound motor C. DC series motor D. DC differential compound motor 44. Armature reaction is attributed to A. the effect of magnetic field set-up by the armature current B. the effect of magnetic field set-up by the field current C. copper loss in the armature D. the effect of magnetic field set-up by back emf 45. What will happen if the supply terminals of a dc shunt motor are interchanged? A. Motor will stop B. Motor will run at its normal speed in the same direction as it was running C. The direction of rotation will reverse D. Motor will run at a speed lower than the normal speed in the same direction 46. When the electric train is moving down a hill the dc motor acts as A. dc series motor B. dc shunt motor C. dc series generator D. dc shunt generator 47. Which of the following motors is suitable for high starting torque? A. shunt motor B. cumulative compound motor C. series motor D. compound motor 48. For which of the following dc motors is the typical field of application mentioned? A. shunt motor : electric trains B. series motor : machine tools C. series motor : belt drive D. compound motor : fly wheel drive 49. Why is the air gap between stator and armature of an electric motor kept as small as possible? A. to get a stronger magnetic field B. to make the rotation easier C. to reach a higher speed of rotation D. to improve the air circulation 50. Interpoles are meant for A. increasing the speed of the motor B. decreasing the counter emf C. reducing sparking at the commutator D. converting armature current to dc 51. Which of the following methods is most economical for finding the no-load losses of a large dc shunt motor is A. Hopkinson’s test B. Swinburne’s test C. retardation test D. none of these A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 28 of 94 D.C. MOTORS 52. The rated speed of a given dc shunt motor is 1050 rpm. To run this machine at 1200 rpm. Which of the following speed control scheme will be used? A. armature current resistance control B. field resistance control C. Ward-Leonard control D. none of these 53. It is preferable to start a dc series motor with some mechanical load on it because A. it will not run at no load B. it acts as a starter to the motor C. it may develop excessive speed and damage itself D. none of these 54. If the flux of a dc motor approaches zero, its speed will approach A. infinity B. zero C. a stable value nearer to the rated speed D. unity 55. A 230 V dc series motor is connected to 230 V ac. It will A. run slowly B. not run at all C. run with less efficiency D. run faster than its rated speed 56. The main function of a commutator in a dc motor is to A. prevent sparking B. convert ac to dc C. reduce friction D. convert dc to ac 57. Which of the following statements is incorrect? If a starter is not used with large dc motor, it will draw a starting current which A. is many times its full-load current B. will produce excessive line voltage drop C. will damage the commutator D. will produce very slow starting torque A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 29 of 94 A.C. FUNDAMENTALS 1. When using circuit laws and rules we must use A. maximum value B. effective value C. average value D. peak to peak value 2. A 60 Hz frequency would cause an electric light to A. turn on and off 120 times per second B. flicker noticeable C. turn on and off 180 times per second D. turn on and off 60 times per second 3. The relationship between frequency f, number of revolutions per second N and pair of poles P is given by A. f = n/p B. f = n/2p C. f = np D. f = 2np 4. The difference between peak +ve value and the peak –ve value of an a.c. voltage is called A. maximum value B. average value C. effective value D. peak to peak value 5. The greatest value attained during one half of the cycle is called A. peak value B. average value C. rms value D. effective value 6. The root mean square (r.m.s) value of an a.c. is the same as A. instantaneous value B. effective value C. average value D. maximum value 7. The rms value of a sine wave is equal to A. 0.637 max. value C. 0.506 max. value B. 0.707 max. value D. 1.414 max. value 8. Form factor is defined as A. rms value/peak value C. rms value/average value B. max. value/rms value D. effective value/rms value 9. The value of form factor for a pure sine wave is A. 1.414 B. 0.707 C. 0.637 D. 1.11 10. The value of peak factor for a pure sine wave is A. 1.414 B. 0.707 C. 0.637 D. 1.11 11. If the current and voltage are out of phase by 90 degrees, the power is A. 1.1 V.I. B. maximum C. minimum D. zero 12. If e1 = A sin ωt and e2 = B sin (ωt - Ө) then A. e1 lags e2 by Ө C. e2 leads e1 by Ө B. e2 lags e1 by Ө D. e1 leads e2 by Ө 13. Average value of a sine wave is 2 times the maximum value A. True B. False C. Partly true D. Partly false A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 30 of 94 A.C. FUNDAMENTALS 14. Which of the following frequencies has the longest period? A. 1 Hz B. 10 Hz C. 1 kHz D. 100 kHz 15. RMS value and the mean value is the same in case of A. square wave B. sine wave C. triangular scale D. half wave rectified sine wave 16. When the sole purpose of an alternating current is to produce heat, the selection of conductor is based on A. average value of current B. peak value of current C. rms value of current D. any of the above 17. The form factor of dc supply voltage is always A. infinite B. zero C. 0.5 18. The period of the voltage 2 cos 4500t + 7 sin 7500 t is A. 2.51 s B. 2.51 ns C. 2.51 ms D. unity D. 2.51s A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 31 of 94 A.C. CIRCUITS (SERIES AND PARALLEL) 1. The total voltage in a series RL circuit A. lags, of 90o C. leads, between 0o and 90o _ the current by an angle _. B. lags, between 0o and 90o D. leads, between 90o and 180o 2. In a series RL circuit, the inductor current A. lags B. leads 3. The impedance triangle is similar to the _. A. current, resistor current C. voltage, impedance the resistor current. C. is equal D. is negative triangle with the resistance phasor in place of the B. current, resistor voltage D. voltage, resistor voltage 4. In the impedance triangle, the inductive reactance and impedance phasor are analogous to the _ and phasor respectively in the voltage triangle. A. inductive voltage, total voltage B. inductive current, total current C. inductive voltage, resistive voltage D. inductive current, resistive current 5. In a series RL circuit phasor diagram, total voltage may be presented by the the resistor voltage may be represented by the phasor. A. current, voltage B. current resistance, current C. impedance, resistance D. impedance, inductance _ phasor and 6. The phase angle of a series RL circuit is the angle between the phasor and the phasor. A. resistance, inductive reactance B. resistance, impedance C. inductive reactance, impedance D. inductance, impedance _ 7. The phase angle of a series RL circuit may be computed as or or A. cos–1 R/XL, sin–1 XL/R, tan–1 R/Z B. cos–1 R/Z, sin–1 XL/R, tan–1 R/XL C. cos–1 Z/XL, sin–1 R/Z, tan–1 XL/R D. cos–1 R/Z, sin–1 XL/Z, tan–1 XL/R . 8. A(n) _ stores and returns energy to a circuit while a(n) _ dissipates energy. A. resistor, impedance B. resistor, inductor C. inductor, resistor D. inductor, reactance 9. For an RL circuit, the power factor cannot be less than A. 0, 1 B. 1, 0 C. 0, –1 10. The voltage across a capacitor A. lags, 45o B. lags, 90o or greater than D. –1, 0 _ the current thought it by C. leads, 0o . D. leads, 90o 11. If the resistance in a series RC circuit is increased the magnitude of the phase angle A. increases B. remains the same C. decreases D. changes in an indeterminate manner 12. In a series RC circuit, the current A. lags, of 45o C. leads, between 0o and 90o the total voltage by an angle B. lags, of 0o D. leads, of 90o A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 32 of 94 . . A.C. CIRCUITS (SERIES AND PARALLEL) 13. The resistance phasor for a series RC circuit points out to the right. The capacitive reactance phasor points while the diagonal of the rectangle having there two phasors as sides represents the . A. up, impedance B. down, impedance C. left, current D. up, total voltage 14. The phase angle for a series RC circuit is defined as the angle between the _ phasors A. current, resistance voltage B. current, total voltage C. resistance voltage, capacitor voltage D. R, XC and the 15. The phase angle for a series RC circuit may be computed as the angle between the phasors A. resistance, impedance B. resistance, reactance C. resistance, capacitance D. impedance, reactance 16. The net reactance in a n RLC circuit is A. XL B. XC C. XC – XL and D. XL – XC 17. The impedance of a series RLC circuit is 2 2 A. R 2 XL C. R 2 (XL X C ) 2 XC 2 2 B. R 2 XL D. R 2 ( X L X C )2 XC 18. There will _ be a frequency, called the frequency at which A. sometimes, natural; XL = XC B. always, natural; R = 0 C. always, resonant; XL = XC D. sometimes, resonant; R = 0 . 19. The formula for the resonant frequency is f = A. LC B. 1 LC C. 2 LC 20. For a series RLC circuit at resonance the current amplitude is amplitude and the power factor is A. minimum, zero B. minimum, unity C. maximum, zero D. maximum, unity D. _ and for a fixed voltage 21. In an RLC circuit, the impedance at resonance is A. maximum, B. minimum C. infinity D. zero 22. The current in RLC series circuit, i.e. at resonance is A. maximum B. minimum C. infinity D. zero 23. In RLC A. B. C. D. 1 2 π LC circuits, the current at resonance is maximum in series circuit and minimum in parallel circuit maximum in parallel circuit and minimum in series circuit maximum in both the circuits minimum in both the circuits A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 33 of 94 A.C. CIRCUITS (SERIES AND PARALLEL) 24. A series resonant circuit is capacitive at f = 100 Hz. The circuit will be inductive somewhere at A. f < 100 Hz B. f > 100 Hz C. f = 100 Hz by increasing the value of the resistance D. f = 0 25. At a frequency lass than the resonant frequency A. series circuit is capacitive and parallel circuit is inductive B. series circuit is inductive and parallel circuit is capacitive C. both circuits are inductive D. both circuits are capacitive 26. In series as well as parallel resonant circuits, increasing the value of resistance would lead to A. increase in the bandwidth of both the circuits B. decrease in the bandwidth of both the circuits C. increase in bandwidth in series circuit and decrease in parallel circuit D. decrease in bandwidth in series circuit and increase in parallel circuit 27. The value of current at resonance in a series RLC circuit is affected by the value of A. R B. C C. L D. all of these 28. In resonant circuits, the power factor at resonance is A. zero B. 1 C. 0.5 D. 0.707 29. Which of the following statements is true for a series RLC circuit tuned at resonant frequency? A. the voltage across C > applied voltage B. the voltage across L > applied voltage C. the voltage across L and C > the applied voltage D. the voltage across both L and C < the applied voltage 30. The frequency at which maximum voltage occurs across the inductance in RLC series circuit is 1 1 1 1 A. D. B. C. 2 LC C2R 2 LC C 2R 2 2 LC R 2 2 π LC 2 2 2 31. The frequency at which maximum voltage occurs across the capacitance in RLC series circuit is A. 1 2 LC B. 1 1 R2 2 π LC 2L2 C. 1 R2 2 LC 2L2 D. 2 1 1 R 2 LC 2 2L 32. If f1 and f2 are half power frequencies and f0 be resonance frequency, the selectivity of RLC series circuit is given by A. f2 f0 B. f2 f1 D. f2 f1 C. f2 f1 f1 f0 f0 2f0 f1 f0 33. In a series RC circuit, the voltage across the capacitor and the resistor are 60 V and 80 V respectively. The input voltage should be A. 7045o V B. 100–37o V C. 105–42o V D. 108–60o V A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 34 of 94 A.C. CIRCUITS (SERIES AND PARALLEL) 34. To a series RLC circuit, a voltage of 10 V is applied. If Q of the coil at resonant frequency is 20, the voltage across the inductor at resonant frequency will be A. 200 V B. 100 V C. 75 V D. 50 V 35. The currents flowing in L and C at parallel resonance are A. zero B. equal C. infinite D. different 36. The exact natural frequency of free oscillations in an oscillatory circuit with capacitance of 0.055 F, inductance 2H and resistance 1 ohm will be A. 478 kHz B. 337 kHz C. 272 kHz D. 192 kHz 37. A coil with large distributed capacitance has a A. low resistance C. low resonant frequency 38. The transient currents are due to A. voltage applied to circuit B. impedance of the circuit B. low Q D. high resonant frequency B. resistance of the circuit D. changes in stored energy in inductance and capacitance 39. To a highly inductive circuit, a small capacitance is added in series. The angle between voltage and current will A. increase B. decrease C. remain nearly the same D. become indeterminate A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 35 of 94 3-PHASE SYSTEM 1. In a balanced three phase star connected circuit the line voltages are equal A. to the line current B. to the phase voltage C. and so are the line currents D. but the line currents are unequal 2. The type of a.c. distribution system commonly used to supply both light and power is the A. open delta system B. three phase delta system C. three phase star system with neutral wire D. three phase star system without neutral wire 3. The phase displacement between phasors in polyphase system is always A. 90 degrees B. 30 degrees C. 120 degrees D. 360 degrees divided by the number of phases 4. In a balanced three phase star connected system the line voltage is A. the phasor difference of the two phase voltages B. the phasor sum of the two phase voltages C. 0.707 times the phase voltage D. 1.414 times the phase voltage 5. In a star connected system line current is A. 0.707 times the phase voltage B. 1.735 times the phase voltage C. equal to the phase current D. 1.414 times the phase voltage 6. The advantages of star connections over delta connections for some phase voltage is that it gives A. step down current B. extra step up voltage C. extra step up current D. extra step up power 7. Power in a three phase star system is equal to A. 3 VL IL power factor C. 3 VL Iph power factor B. 3 Vph IL power factor D. 3 Vph Iph power factor 8. Power in a three phase delta system with balanced load is equal to A. C. 3 VL IL power factor 3 Vph IL power factor 9. In a delta connected system the line current is A. 1.414 times the phase current C. equal to the phase current B. 3 Vph Iph power factor D. 3 VL IL power factor B. phasor sum of the two phase currents D. 1.732 times the phase current 10. Power in star connected system is A. equal to that of delta system B. C. D. 3 times that of delta system 3 times that of delta system 2 times that of delta system A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 36 of 94 3-PHASE SYSTEM 11. For an unbalanced load which connection is suitable A. 3 wire open delta B. 4 wire star connection C. 3 wire delta connection D. 3 wire star connection 12. What is the minimum number of wattmeters required for measuring power of a three phase balanced load? A. two B. four C. one D. three 13. The power is to be measured for a balanced delta connected load whose terminals cannot be opened. How many wattmeters do you need? A. four B. one C. two D. three 14. What is the minimum number of wattmeters required to measure unbalanced power for a three phase system? A. two B. four C. three D. one 15. In two wattmeter method, the readings of the wattmeter will be identical when A. load in one of the phases is zero B. power factor is unity C. power factor is 0.5 D. neutral is earthed 16. Two wattmeters can be used to measure 3-phase power for a A. balanced and unbalanced load B. unbalanced load only C. balanced load only D. unity power factor only 17. In two wattmeter method, the reading of one of the wattmeter will be zero when A. power factor is unity B. power factor is 0.5 C. load in one of the phases is zero D. a neutral wire is not provided 18. For a three phase unbalanced load A. the power factor of each phase will be in proportional to the load B. the power factor of each phase will be the same C. the power factor of at least one of the phase must be leading D. the power factor of each phase may be different A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 37 of 94 POWER FACTOR 1. In a pure reactive circuit, the power factor is A. lagging B. zero C. leading 2. Power factor is defines as the ratio of A. volt amperes to watts C. volt amperes reactive to watts B. watts to volt amperes D. watts to volt amperes reactive D. unity 3. In a series circuit consisting of resistance and reactance, power factor is defined as the ratio of A. resistance to impedance B. resistance to reactance C. reactance to impedance D. reactance to resistance 4. For a parallel circuit consisting of resistance and reactance, the value of power factor is the ratio of A. impedance to reactance B. reactance to impedance C. resistance to impedance D. impedance to resistance 5. It is not easy to find the value of impedance for a parallel circuit but power factor can easily be obtained as a ratio of A. active current to line current B. reactive current to line current C. line current to active current D. line current to reactive current 6. The power factor of a.c. circuit containing both a resistor and a conductor is A. more than unity B. leading by 90 degrees C. between 0 – 1 leading D. between 0 – 1 lagging 7. In an a.c. circuit, a low value of reactive volt ampere compared with watts indicates A. high power factor B. unity power factor C. leading power factor D. low power factor 8. In a given circuit when power factor is unity the reactive power is A. a maximum B. equal to I2R C. zero D. a minimum 9. The capacitor of power factor correction are rated in terms of A. voltage B. VA C. kW D. kVAR 10. Poor power factor results in all of the following except A. overloading of transformers B. overloading of alternators C. reduction in power losses D. reduction in load handling capacity of electrical system 11. Power factor of an inductive circuit can be improved by connecting a capacitor to it in A. series B. parallel C. either series or parallel D. depends on the value of the capacitor 12. For the same load, if the power factor of load is reduced, it will A. draw more current B. less current C. same current but less power D. less current but more power 13. The power factor of incandescent bulb is A. 0.8 lagging B. 0.8 leading C. unity D. zero A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 38 of 94 POWER FACTOR 14. Power factor of magnetizing component of a transformer is A. unity B. 0.8 leading C. always leading D. zero 15. One of the reasons for improving the power factor is A. to increase the reactive power B. to decrease the reactive power C. to increase the real power D. none of these 16. Another reason for improving the power factor is A. to avoid poor voltage regulation B. to keep voltage regulation constant C. to increase the voltage regulation D. to decrease the voltage regulation 17. Power factor improvement may be achieved by the use of A. synchronous motor B. induction motor C. long transmission line D. short transmission line 18. The advantage of using static capacitor to improve the power factor is because they A. are not variable B. are almost loss free C. provide continuous change of power factor D. all of the above 19. Many industrial tariffs penalize consumers whose power factor falls A. below 0.8 B. below unity C. between 0.8 to 0.95 D. between 0.95 to unity 19. A factory takes a load of 1000 KW and has a reactive power of 1000 KVA. Its power factor is A. 0.6 B. unity C. 0.8 D. 0.7 20. A current of 10 amperes at a power factor of 0.8 lagging is taken from 250 V a.c. supply. The reactive power of the system is A. 2000 watts B. 2000 VA C. 1500 watts D. 1500 Var A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 39 of 94 NETWORK THEOREMS 1. Kirchhoff’s voltage law is not valid for a non-linear network. A. True B. False C. Partly true D. Partly False 2. Kirchhoff's law is applicable to A. AC circuits only C. AC as well as DC circuits B. passive networks only D. DC circuits only 3. An ideal current source has zero A. voltage on no load C. internal conductance B. internal resistance D. current 4. A closed path made of several branches of the network is known as A. loop B. junction C. branch D. division 5. An ideal voltage source is that which A. has terminal voltage in proportion to current B. has zero internal resistance C. has terminal voltage in proportion to load D. has terminal voltage in proportion to power 6. A passive network has A. no source of emf B. no source of current C. neither source of current nor source of emf D. none of these 7. Which of the following is an active element of a circuit? A. ideal current source B. resistance C. inductance D. capacitance 8. The relationship between voltage and current is same for two opposite directions of current in case of A. bilateral network B. active network C. unilateral network D. passive network 9. Which of the following statement is not correct? A. voltage source is an active element B. current source is a passive element C. resistance is a passive element D. conductance is a passive element 10. A network is said to be non linear if it does not satisfy A. homogeneity condition B. superposition condition C. both A and B D. associative condition 11. Which of the following statement is not correct? A. Ideal voltage source is one whose internal conductance is zero. B. Ideal current source is one whose internal conductance is zero. C. Ideal voltage source is one whose internal resistance is zero. D. Ideal voltage source is one whose generated voltage is equal to the available terminal voltage. A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 40 of 94 NETWORK THEOREMS 12. Which of the following is not a non-linear element? A. diode B. transistor C. heater coil D. electric arc with unlike electrodes 13. Which of the following theorems enables a number of voltage (or current) source to be combined directly into a single voltage (or current) source? A. compensation theorem B. reciprocity theorem C. superposition theorem D. Millman’s theorem 14. Thevenin’s theorem is applicable to network of A. ac circuit only C. ac and dc circuit both B. dc circuit only D. none of the above 15. For open circuited condition of Thevenin’s theorem, all sources of emf in the network are replaced by A. their internal impedance B. their internal resistance C. as a total a big source of emf D. their internal reactance 16. The current in any branch of a network in case of Thevenin’s theorem is the same as if it were connected to a generator of A. different rating B. emf E1 and internal impedance Z1 C. low rating D. emf E1 and internal impedance zero 17. In order to find Z in Thevenin’s theorem A. all independent voltage and current sources are short circuited B. all independent voltage sources are short circuited and independent current sources are open circuited C. all independent current sources are short circuited and independent voltage sources are open circuited D. all independent voltage sources are open circuited and independent current sources are open circuited 18. Regarding Thevenin’s equivalent, which of the following is not correct? A. The voltage source in the Thevenin equivalent circuit is the open circuit voltage of the network when load is disconnected. B. The Thevenin equivalent resistance (impedance) is the resistance (impedance) of the network when all voltage sources are short circuited. C. Thevenin equivalent resistance is calculated when all voltage sources are open circuited. D. Thevenin equivalent is the voltage equivalent of the network. 19. Regarding Norton’s equivalent, which of the following is not correct? A. Norton’s equivalent is the voltage equivalent of the network. B. Norton’s equivalent is the current equivalent of the network. C. Norton’s equivalent resistance is the same as the Thevenin equivalent resistance. D. The load is connected in parallel to the Norton equivalent resistance and Norton's equivalent source. 20. Reciprocity theorem is valid for A. active network only C. active and passive network both B. passive network only D. none of the above A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 41 of 94 NETWORK THEOREMS 21. For reciprocity theorem to be applicable to a network in which A. generators are present B. capacitor is present C. inductor is present D. generators are not present 22. In compensation theorem a network containing generator can be replaced by A. its zero internal impedance B. its infinite impedance C. another generator D. L.C. circuit 23. The most important feature of superposition theorem application is A. that the process is eased very much B. to find d.c. level in e network that has both sources C. that number of equations needed to be solved is reduced very much D. none of the above 24. Open circuit voltage is the potential difference between two points when the impedance between these points is A. infinity B. reactive C. zero D. capacitive 25. Norton’s theorem reduces a two terminal network to A. a constant voltage source and an impedance in parallel B. a constant voltage source and an impedance in series C. a constant current source and an impedance in parallel D. a constant current source and an impedance in series 26. For the same original network end load, Thevenin’s and Norton’s equivalent circuits are related by A. Eth = InZth = InZn B. Eth = IthZn = IthZth C. Zn = Eth/Ith D. Zth = En/In 27. If an electrical network having one or more than one voltage source, is transformed into equivalent electrical network with a single voltage source (which is short circuit current of previous circuit) with parallel internal resistance of the network with all current source replaced by their internal resistance. The above illustration is called A. Thevenin’s theorem B. Reciprocity theorem C. Norton’s theorem D. Superposition theorem 28. The superposition theorem requires as many circuits to be solved as there are A. meshes B. nodes C. sources D. all of the above 29. For maximum power transfer, according to maximum power transfer theorem, source impedance A. must be very much large as compared to the load impedance B. must be complex conjugate of load impedance C. must be equal to load impedance D. must be very small as compared to the load impedance 30. In case of delta connected circuit, when one resistor is open, power will be A. unaltered B. reduced by 1/3 C. reduced to 1/9 D. reduced to 1/16 31. A source V has an internal impedance Zin = (R + jX) when it is connected ZL = R – jX the power transferred is A. V2/4R2 B. V2/4R C. V2/R D. V2/2R A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 42 of 94 NETWORK THEOREMS 32. The superposition theorem is applicable to A. linear responses only B. linear and non-linear responses only C. linear, non-linear and time variant response D. non-linear responses only A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 43 of 94 TRANSFORMERS 1. The principle of working of a transformer is A. static induction C. mutual induction B. dynamic induction D. self induction 2. Transformer is used to change the values of A. frequency B. voltage C. power 3. The path of the magnetic flux in a transformer has A. low reactance B. high reactance C. high conductivity D. power factor D. low resistance 4. Electric power is transformed from one coil to the other coil in a transformer A. physically B. magnetically C. electrically D. electromagnetically 5. A transformer operates A. always at unity power factor B. has its own power factor C. at power factor below a particular value D. at power factor depending on the power factor of the load 6. The laminations are made from A. low carbon steel C. nickel alloy steel stampings B. silicon steel sheet D. chrome steel sheets 7. The steel for construction of transformer core is made so as to have A. low permeability and high hysteresis B. low permeability and low hysteresis C. high permeability and low hysteresis D. high permeability and high hysteresis loss 8. The special silicon steel is used for laminations because A. hysteresis losses are reduced B. eddy current losses are reduced C. both the above losses are reduced D. none of these 9. What is common in the two windings of a transformer? A. electric circuit B. magnetic circuit C. winding wire gauge D. dielectric circuit 10. The main function of the iron core in a transformer is to A. provide strength to the windings B. to decrease the hysteresis loss C. decrease the reluctance of the magnetic path D. reduce eddy current losses 11. Preferably, the resistance between the primary and the secondary of a transformer should be A. as low as possible B. as high as possible C. low or high depending upon whether it is step up or step down respectively D. high or low depending upon whether it is step up or step down respectively 12. Ideal transformer assumptions do not include A. zero reactance of windings C. no leakage flux B. zero resistance of windings D. no saturation of core A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 44 of 94 TRANSFORMERS 13. The reactance of a transformer is determined by its A. leakage flux B. common core flux C. size of the core D. permeability of the material of the core 14. The efficiency of a transformer is normally in the range of A. 50% to 70% B. 60% to 75% C. 80% to 90% D. 90% to 98% 15. The resistance of low voltage side of a transformer A. is equal to resistance of its high voltage side B. is more than the resistance of its high voltage side C. is less than the resistance of its high voltage side D. B or C 16. Eddy current losses in transformer core are reduced by A. increasing the thickness of laminations B. decreasing the thickness of laminations C. taking the wire of higher gauge for winding the transformer D. decreasing the air gap in the magnetic circuit 17. The primary and the secondary voltages are A. 180 degrees out of phase in a transformer B. always in phase in a transformer C. 90 degrees out of phase in a transformer D. 30 degrees or 60 degrees our of phase in a transformer 18. The basic property of the transformer is that it changes the voltage level of an a.c. signal A. without changing the power B. without changing its shape C. without changing its frequency D. without changing power, frequency or shape 19. Eddy current losses in a transformer are minimized by laminating the core, the lamination being insulated from each other by A. a light coat of core plate varnish B. thin sheet of mica C. thick paper of insulation D. any one of the above 20. The induced emf in the transformer secondary will depend upon A. maximum flux in core and frequencies only B. frequency, flux and number of turns in the secondary C. frequency of the supply only D. number of turns in secondary only 21. At every instant, the direction of secondary current in a transformer must be such as to oppose any change in flux. This is in accordance with A. Faraday’s law B. Joule’s law C. Lenz’s law D. Coulomb’s law 22. The voltage transformer ratio is A. E1/E2 B. N1/N2 C. E2/E1 D. N2/N1 A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 45 of 94 TRANSFORMERS 23. The magnitude of mutual flux in a transformer is A. low at low loads and high at high loads B. high at low loads and low at high loads C. same at all levels D. varies at low loads and constant at high loads 24. The concentric windings are used in core type transformer with A. LT winding placed next to core B. HT winding placed next to core C. LT winding on the outer side D. HT winding on the outer side 25. Cross-over windings are used for A. high voltage winding of small rating transformers B. low voltage winding of small rating transformers C. high voltage winding of large rating transformers D. low voltage winding of large rating transformers 26. In an ideal transformer on no-load, the primary applied voltage is balanced by A. the secondary voltage B. the drop across resistance and reactances C. the secondary induced emf D. the primary induced emf 27. Transformers are rated in A. kW B. kV C. kWH 28. What type of core is used for a high frequency transformer? A. air core B. closed iron core C. aluminum core D. kVA D. open iron core 29. If in a transformer the secondary turns are doubled and as the same time the primary voltage is reduced by half, then the secondary voltage will A. be halved B. not change C. be four times as high D. be reduced to a quarter 30. The no-load current of a transformer in terms of full load current is usually A. 1 to 3% B. 3 to 9% C. 9 to 12% D. 12 to 20% 31. Which is the common method of cooling a power transformer? A. air cooling B. air-blast cooling C. oil cooling D. natural cooling 32. Which of the following is a correct statement about eddy currents? A. Eddy currents improve the efficiency of a motor. B. Eddy currents heat up the metal parts. C. Eddy currents do not influence the movement. D. Eddy currents are used for arc welding. 33. Which of the statement given below is true about autotransformer? A. It has two separate windings connected in series externally. B. It can only step down the voltage. C. It has only one winding. D. It is most suitable for power transformation. A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 46 of 94 TRANSFORMERS 34. The use of higher flux density in transformer design A. decreases the weight per kVA B. increases the weight per kVA C. increases the weight per kW D. decreases the weight per kW 35. What is the efficiency of transformer compared with that of electrical motors of the same power? A. much smaller B. somewhat smaller C. much higher D. about the same 36. The transformer oil used in transformers provide A. cooling and lubrication B. insulation and lubrication C. insulation and cooling D. insulation, cooling and lubrication 37. What is the typical use of an autotransformer? A. Toy transformer C. Variable Transformer B. Control transformer D. Isolating Transformer 38. In any transformer the voltage per turn in primary and secondary remains A. always different B. always same C. always in ratio of k D. sometimes same 39. The full load copper loss in a transformer is 400 watts. At half load, the copper loss will be A. 400 watts B. 100 watts C. 200 watts D. 50 watts 40. A transformer is working at its maximum efficiency. Its iron loss is 500 watts. Its copper loss will be A. 300 watts B. 250 watts C. 350 watts D. 500 watts 41. Power transformers are designed to have maximum efficiency at A. no load B. half load C. near full load D. little more than full load 42. As compared to an amplifier a transformer cannot A. increase output power B. increase the output current C. increase the output voltage D. decrease the output current 43. Distribution transformers have good all-day efficiency due to A. low copper loss B. low iron loss C. low copper as well as iron loss D. low power loss 44. In transformer the purpose of breather is to A. extract moisture of the air C. to provide cooling to the winding B. to take insulating oil from conservator D. to provide insulation to the winding 45. Two transformers when operating in parallel will share the load depending upon their A. magnetizing current B. leakage reactance C. per unit impedance D. efficiency 46. The magnetic coupling between the primary and secondary windings of a transformer may be increased by A. increasing the number of laminations of core material B. using the magnetic core of low reactance C. changing the turns ratio of the transformer D. no means, because it is constant A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 47 of 94 TRANSFORMERS 47. Conservator consists of A. an air-tight metal drum fixed at the top of the tank B. drum placed at the bottom of the tank C. overload protection D. none of these 48. For a three phase transformer, turns ratio k is given as A. k 3 line voltage ratio B. k line voltage ratio C. k 3 phase voltage ratio D. k phase voltage ratio 49. In a power transformer, the winding which is nearer to the iron core of the transformer A. is a H.V. winding B. is L.V. winding C. may be H.V. or L.V. winding D. is sandwiching of the two windings 50. All day efficiency of a transformer A A. A = electrical efficiency of transformer B. A > electrical efficiency of transformer C. A < electrical efficiency of transformer D. none these may be true 51. If we increase the flux density in the case of a transformer A. the size of the transformer will reduce B. the distortion in the wave shape will reduce C. the hysteresis and eddy current losses will reduce D. none of the above is true 52. A good transformer oil should be absolutely free from A. sulphur B. alkalies C. moisture D. all of the above 53. In an ideal transformer on no load, the voltage applied across the primary winding of the transformer is balanced by A. the emf induced in the primary winding B. the drop across the impedance of primary side C. the drop across the impedance of secondary side D. the secondary induced emf 54. No load primary input is practically equal to the iron losses in the transformer because A. primary current is small B. secondary current is small C. both the currents are small D. no load is not equal to iron losses 55. The transformation of energy from primary of the transformer to secondary takes place due to A. the flux linkage between the two windings B. the difference in number of turns of primary and secondary windings C. the changing current in two windings D. none of these 56. If Rs is the resistance of secondary winding of the transformer and k is transformation ratio then the equivalent secondary resistance referred to primary side will be Rs Rs Rs Rs B. C. A. D. 2 3 k k k k A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 48 of 94 TRANSFORMERS 57. Mark the correct statement. A. The percentages of resistance, reactance and impedance have the same value whether referred to primary or secondary of the transformer. B. A good transformer must have regulation as high as possible. C. If the power factor is leading the regulation of a good transformer will be higher than when it is lagging. D. None of the above is correct. 58. If the supply frequency to the transformer is increase, the iron loss will A. decrease B. increase C. do not change 59. The size of a transformer core will depend on A. frequency C. area of the core D. vary B. flux density of the core material D. A and B both 60. Two transformers operating in parallel will share the load depending upon their A. rating B. leakage reactance C. efficiency D. per unit impedance 61. Three 10 : 1 single phase, step-down transformers are connected in wye-delta. For a primary line-toline voltage of 3980 V, find the corresponding line voltage on the secondary side. A. 398 V B. 230 V C. 3980 V D. 2300 V 62. While conducting short-circuit test on a transformer, the following side is short-circuited: A. H.V. side B. L.V. side C. Primary side D. Secondary side 63. Current transformer secondary is connected to an ammeter of 5 A range to measure line current of 1000 A. The ammeter is to be serviced. It can be removed A. without interfering with supply B. with interfering with supply C. only after switching off the main current path D. only before switching off the main current path A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 49 of 94 ALTERNATORS 1. In huge alternators, the moving part is A. brushes B. armature C. poles 2. In case of alternator, the stator frame serves A. to protect the whole machine C. to hold the armature stampings B. as a return path for the flux D. to verticate the armature D. rotor 3. Alternators mostly work on rotating field type principle which is different from d.c. machines where the field is stationary. Therefore alternators A. don’t obey Faraday’s law B. work on Faraday’s law C. do not obey Lenz’s law D. don’t obey Ohm’s law 4. High speed alternators have a rotor construction A. similar to dc machines B. of non-salient type C. of salient type D. of silent type 5. The voltage applied to the field of a rotating cylindrical rotor type alternators A. high dc voltage B. high ac voltage C. low dc voltage D. low ac voltage 6. Alternators are usually designed to generate A. variable frequency C. definite frequencies B. definite currents D. definite power factor 7. The standard practice, nowadays in alternators is to have A. rotating field B. rotating armature C. either rotating field or rotating armature D. none of the above 8. In power generating stations (thermal stations) the usual number of poles employed in alternators are A. twenty four B. forty eight C. thirty two D. none of these 9. The diameter of high speed turbo alternators as compared to hydroelectric ones are A. smaller because speed is high B. smaller because speed is less C. larger because speed is high D. larger because speed is less 10. The slip rings employed in a three-phase alternator in hydrostation are insulated for A. extra high tension voltage B. low voltage C. full armature voltage D. very high voltage 11. When the speed of an alternator increases, the frequency A. decreases B. remains the same C. increases D. changes 12. Steam-turbo alternators are much smaller in size than water-turbine alternators for a given output. This is so because A. steam-turbo alternators are built with smaller capacities B. steam-turbo alternators run at high speed C. steam-turbo alternators have long rotors D. all of these A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 50 of 94 ALTERNATORS 13. For a coil having a span of 2/3 or pole pitch, the coil span factor is A. 0.8 B. 0.866 C. 0.786 D. 0.966 14. Distributing the armature winding of alternator is more than one number of slots per pole per phase results in A. reduction of irregularities produced in the waveform B. economy of materials used in winding C. less weight of the entire armature D. increase of generated emf per phase 15. When the power factor of load is unity, the armature flux of an alternator will be A. demagnetizing B. square wave form C. cross magnetizing D. none of these 16. An alternator is capable of delivering power at a particular frequency. The frequency can be increased by A. increasing the armature speed B. reversing the armature rotation C. increasing the current supplied to the field electromagnets D. reversing the field polarity 17. If the input of the prime mover of an alternator is kept constant but excitation is increased then A. kVA will be leading B. kVA will be lagging C. kW will be changed D. the power factor of the load remains constant 18. For two alternators operating in parallel, if the load shared by one of them is to be increased, its field excitation is A. to be strengthened keeping input torque the same B. to be weakened keeping input torque the same C. to be kept constant but input torque should be increased D. to be kept constant but input torque should be decreased 19. If P = number of pair poles, f = the frequency in Hz, S = speed in rpm, the relationship between the three for synchronous alternators is given as PS fS fP PS Hz B. P poles C. f Hz D. S rpm A. f 120 120 120 60 20. If Ө is the angle measured in electrical degrees between any point on the pole face and center of the pole then for setting a sinusoidal wave as output, the air gap at that point should be such that A. air gap α sin B. air gap α cos 1 1 D. air gap α C. air gap α cos θ sin 21. The sinusoidal voltage developed per pole per phase in a group of coils is defined as A. Egap = 4.44NnfkdkpV B. Egap = 4.44NfkdkpV C. Egap = 4.44NkffV D. none of these Where N = no. of turns per coil n = no. of coils per phase per pole A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 51 of 94 ALTERNATORS 22. The armature reaction of an alternator will be cross-magnetizing of the power factor of the load is A. unity B. less than unity C. more than unity D. zero leading 23. If XS = the synchronous reactance of the machine, Xe = leakage reactance and Xa = reactance due to armature flux then A. Xa = XS – Xe B. Xa = XS + Xe C. Xa = Xe – XS D. Xe = XaXS 24. The best and the most accurate method for determining the voltage regulation is A. synchronous impedance method B. mmf method C. emf method D. Potier triangle method 25. An alternator is said to be over-excited if it is operating at A. leading p.f. B. lagging p.f. C. unity p.f. D. zero voltage regulation 26. From what source does a rotating field type alternator receive its exciter voltage? A. from an externally controlled ac voltage B. from an externally controlled dc voltage C. from a self excited source like shunt generator D. from an auxiliary generator driven by main generator shaft 27. High voltage alternators are usually of the rotating field type. This means the generated voltage is connected A. through slip rings to the load B. through slip rings of the rotating field C. directly to the load D. directly to the rotor 28. The maximum current that can be supplied by alternators depends upon the A. strength of the excite voltage B. number of poles C. strength of the magnetic field D. maximum heat dissipation 29. One of the advantages of distributing the winding in alternators is to A. reduce harmonics B. improve voltage wave form C. reduce the amount of copper D. decrease the value of the voltage 30. Distribution factor K4 is defined as the ration of emf’s of A. distributed winding to full pitch winding B. concentrated winding to distributed winding C. distributed winding to concentrated winding D. full pitch winding to distributed winding 31. If n = number of slots per pole per phase and α = slot angle, the distribution factor is A. n sin / 2 B. sinn / 2 sin / 2 n sin / 2 2 C. sinn D. sin n α /2 n sin / 2 nsin α /2 32. For a uniformly distributed winding the value of distribution factor is A. unity B. 0.96 C. 0.866 D. 0.955 A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 52 of 94 ALTERNATORS 33. One of the advantages of a short pitch winding lies in A. elimination or suppression of harmonics B. reduction of voltage C. increasing the inductance D. reduction of the circulating current 34. Pitch factor is defined as the ratio of the emf’s of A. distributed winding to full pitch winding B. short pitch coil to full pitch coil C. full pitch winding to short pitch winding D. full pitch winding to concentrated winding 35. A winding is short pitched by 60 degrees electrical. Its pitch factor is A. 0.5 B. 0.866 C. 0.707 D. 0.966 36. Synchronous impedance of an alternator is defined as the ratio of A. short circuit voltage to short circuit current B. open circuit voltage to short circuit current C. short circuit current to no load current D. open circuit voltage to short circuit current for same value of excitation 37. Synchronous reactance consists of two components, namely A. armature resistance and leakage reactance B. leakage reactance and fictitious reactance C. armature resistance and fictitious reactance D. leakage reactance and capacitive reactance 38. The imaginary or fictitious part of synchronous reactance takes care of A. copper losses B. voltage regulation C. armature reaction D. inductive reactance 39. Regulation of an alternator is defined as the rise in terminal when full load is thrown off expressed as percentage of the terminal for the same value of excitation and speed. A. current B. voltage C. rating D. power factor 40. Synchronization of alternators means A. connecting alternators in series C. connecting alternators in parallel B. transferring load from one alternator to another D. adjusting the excitation of the alternators 41. To synchronize alternator, three conditions must be fulfilled, namely A. same voltage ratio, same frequency and voltages should be in phase with respect to the external circuit B. same voltage, same frequency and voltages should be in phase opposition with respect to the external circuit C. same voltage, same frequency and voltages should be in phase opposition with respect to local series circuit D. same voltage ratio, different frequencies and proper phase relation of the voltages 42. For synchronizing three phase alternators, the additional requirement is that the phase rotation A. must be the same B. is clockwise C. is anti-clockwise D. none of the above A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 53 of 94 ALTERNATORS 43. The method most commonly used for synchronizing the alternators in a power house is: A. dark lamp method and a synchroscope B. dark lamp method only C. bright lamp method D. bright lamp method and a synchroscope 44. In order to transfer the load from one alternator to another alternator, when they are operating in parallel A. field current is increased B. field current is decreased C. speed is decreased D. prime mover power input is increased 45. Adjustment of field excitation on one of the two alternators operating in parallel will A. increase its load B. change its frequency C. decrease its load D. change its power factor 46. Each of two alternators operating in parallel are adjusted for unity power factor. Increasing the field current of one A. causes its power factor to become leading B. causes its power factor to become lagging C. changes its speed D. increases its load 47. What kind of rotor is most suitable for turbo-alternators which are designed to run at high speed? A. salient-pole type B. non-salient pole type C. both A and B D. none of the above 48. Dampers in large generators A. increase stability C. reduce frequency fluctuations B. reduce voltage fluctuations D. decrease stability 49. Short-pitch coils in the alternator are used A. to reduce the size of the alternator B. to reduce the harmonics from the generated emf of the alternator C. to reduce the copper loss in the alternator D. to reduce the core loss in the alternator 50. If the input to the prime-mover of an alternator is kept constant but the excitation is changed then A. the reactive component of the output is changed B. the active component of the output is changed C. the p.f. of the load remains constant D. the p.f. of the load varies 51. The driving power from the prime mover driving an alternator is lost but the alternator remains connected to the supply network and field supply is on. The alternator will A. get burnt B. behaves as an induction motor C. behaves as synchronous motor but will rotate in reverse direction to that corresponding to generator action D. behaves as a synchronous motor and will rotate in the same direction A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 54 of 94 SYNCHRONOUS MOTORS 1. Synchronous motor has A. constant speed C. high speed at low torque B. slight drop in speed on full load D. low speed at high torque 2. The synchronous speed of a 50 cycle 10 pole motor is A. 500 rpm B. 150 rpm C. 600 rpm D. 1000 rpm 3. The speed of a synchronous motor connected to 50 cycle supply is 1000 rpm. The number of poles it must have A. 4 B. 6 C. 8 D. 10 4. The maximum power developed in a synchronous motor occurs at a coupling angle of A. 0 degree B. 45 degrees C. 90 degrees D. 180 degrees 5. A 3-phase, 4 pole, 24 slot alternator has its armature coils short-pitched by one slot. Its pitch factor will be A. 1.0 B. 0.966 C. 0.96 D. 0.94 6. Synchronous motor is capable of being operated at A. lagging power factor only B. leading power factor only C. lagging and leading power factor D. none of these 7. The synchronous motor is not inherently self-starting because A. the rotating magnetic field does not have enough poles B. the rotating magnetic field is produced by only 50 Hz frequency currents C. the force required to accelerate the rotor is to the synchronous speed in an instant is absent D. the starting devices to accelerate the rotor to near synchronous speed is absent 8. When the stator windings are connected in such a fashion that the number of poles are made half, the speed of the rotor of a synchronous motor A. decreases to half the original value B. remains the same as the original value C. increases to two times the original value D. tends to become zero 9. In a synchronous motor, as load is applied, the motor takes more armature current because A. back emf decreases causing an increase in motor current B. the rotor strengthens the rotating field causing more motor current C. the rotor by shifting its phase backward causes motor to take more current D. the increased load has to take more current 10. Synchronizing power of a synchronous machine is A. equal to synchronous reactance B. inversely proportional to the synchronous reactance C. directly proportional to the synchronous reactance D. none of these 11. Synchronous motor always runs at A. a speed less than synchronous speed C. the synchronous speed B. a speed more than synchronous speed D. none of these A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 55 of 94 SYNCHRONOUS MOTORS 12. Synchronous motors are A. self-starting C. essentially self-starting B. not self-starting D. none of these 13. An over-excited synchronous motor take A. lagging current C. lagging and leading current B. leading current D. none of these 14. The motor in which stator and rotor magnetic field rotate at the same speed is A. induction motor B. reduction motor C. universal motor D. synchronous motor 15. When the excitation of an unloaded salient pole synchronous motor suddenly gets disconnected, then A. the motor stops B. it runs at the same speed C. it runs at lower speed D. it runs at very high speed 16. In a synchronous motor, the torque angle is A. the angle between the rotating stator flux and rotor poles B. the angle between the magnetizing current and back emf C. the angle between the supply voltage and the back emf D. none of the above 17. A 3-phase, 400 V, 50 Hz, 4-pole synchronous motor has a load angle of 10 degrees electrical. The equivalent mechanical degree will be A. 10 degrees B. 5 2 degrees C. 5 degrees D. 1 degree 18. The breakdown torque of a synchronous motor varies as 1 1 A. B. applied voltage (applied voltage)2 C. applied voltage D. (applied voltage) 2 19. In a synchronous motor, which loss does not vary with load? A. copper losses B. hysteresis losses C. windage losses D. none of the above 20. A 3-phase, 400 V, 50 Hz salient pole synchronous motor is running on no load. If there is break in the excitation winding of the motor A. the motor will stop B. the winding will get overheated C. the motor will run as reluctance motor at the rated rpm D. the motor will run as reluctance motor at lower rpm 21. A 3-phase synchronous motor is running clockwise. In case the direction of its field current is reversed A. the motor will continue to run in the same direction B. the motor will run in the reverse direction C. the motor will stop D. the winding of the motor will burn A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 56 of 94 SYNCHRONOUS MOTORS 22. The speed regulation of a 3-phase synchronous motor is A. 5% B. 1% C. 0.4% D. zero 23. In a synchronous motor, the synchronizing power comes into action when A. rotor speed is equal to synchronous speed B. rotor speed is less than synchronous speed C. rotor is speed is more than synchronous speed D. rotor speed is either less or more than synchronous speed 24. The speed of a synchronous motor A. reduces as load increases B. increases as load increases C. adjusts itself to new equilibrium speed whenever load changes D. always remains constant 25. The minimum armature current of a synchronous motor corresponds to operation at A. 0.8 power factor lagging B. unity power factor C. zero power factor leading D. zero power factor lagging 26. If the field of a synchronous motor is under-excited the power factor will be A. lagging B. leading C. unity D. more than unity 27. When a 3-phase synchronous generator is supplying a zero p.f. lagging load the armature field affects the main field in the following way: A. directly opposes it B. cross magnetizes it C. augments it directly D. indirectly augments it 28. When the excitation of an unloaded salient-pole synchronous motor suddenly gets disconnected A. the motor stops B. it runs as a reluctance motor at the same speed C. it runs as a reluctance motor at a lower speed D. none of the above 29. In a 3-phase synchronous converter, the ratio of ac current to dc current is equal to A. 0.943 B. 0.612 C. 1.60 D. 0.866 30. The armature current of the synchronous motor has large values of A. low excitation only B. high excitation only C. both low and high excitation D. moderate excitation A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 57 of 94 INDUCTION MOTORS 1. The type of the motor that does not have a commutator is the A. repulsion motor B. induction motor C. dc shunt motor D. ac series motor 2. A certain motor is driven by a 1750 rpm dc shunt motor. If the power supply is to be changed to three phase, 50 cycles ac, the most suitable replacement motor would be A. synchronous motor B. capacitor motor C. ac commutator motor D. squirrel cage induction motor 3. The principle of operation of the induction motor is based on A. Faraday’s law B. rotating magnetic field C. Flemming’s right hand rule D. Ohm’s law 4. The rotor of an induction motor gets its power from A. the line voltage B. slip rings C. a centrifugal switch D. magnetic induction 5. The induction motors are designed for A. three phase C. single phase B. two phase D. all of the above 6. The rotor speed of an induction motor is A. the same as the synchronous speed B. faster than the synchronous speed C. slower than the synchronous speed D. determined by frequency and the number of poles 7. The induction motor differs from the synchronous motor in that it(s) A. requires a dc source for its rotor B. does not require a rotating magnetic field C. current is induced in its rotor D. current I conducted in rotor 8. To reverse the direction of rotation of a three phase induction motor, it necessary to A. interchange all the three line connections B. reverse the polarity of the rotor circuit C. increase the resistance of the rotor circuit D. interchange any two of the three line connections 9. Squirrel cage induction motor differs from the slip ring type in that it has no A. slip rings B. rotor winding C. windings on the stator D. rotating part 10. If the no-load speed of a squirrel cage induction motor connected to a three phase 50 cycle supply is 740 rpm. The motor has A. 2 poles B. 4 poles C. 6 poles D. 8 poles 11. Squirrel cage induction motor has A. zero starting torque B. very high starting current B. very small starting torque D. extra starting torque and it starts up from rest A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 58 of 94 INDUCTION MOTORS 12. Just like a dc shunt motor the speed of induction motor operating in stable region A. decreases with increase in load B. increases with increase in load C. decreases with decrease in load D. none of the above is true 13. Magnetic flux produced due to the stator winding with three-phase current of frequency f and which is the constant value, rotates at synchronous speed. If P is the number of poles of the motor then the synchronous speed is given by 120f A. 120P B. N s Ns f P 60f D. N C. Ns 120fP s P 14. In an induction motor A. rotor runs at a speed equal to the speed of the stator field B. rotor runs at a speed which is always lesser than the speed of the stator field C. rotor runs at a speed which is always higher than the speed of the stator field D. B and C both are correct 15. The difference between the synchronous speed Ns and the actual speed N of the rotor is known as slip. It can be expressed as a percentage and is given by N Ns N N 100 A. % slip S = s B. % slip S = 100 N Ns N Ns C. % slip S = 100 D. % slip S = (Ns S) Ns 16. The frequency of the rotor current in an induction motor is given by (If f is the supply frequency, f’ is the rotor frequency and S is the slip) A. f = Sf’ B. f’ = Sf’ C. f’ = Sf D. S = f f’ 17. Frequency of the rotor in an induction motor in terms of Ns, N and P is given by 120P 120f' B. N N A. N N s s f' P 120 C. N D. none of the above is correct s Pf ' 18. If E2 = rotor emf/phase at standstill R2 = rotor resistance/phase X2 = rotor resistance/phase at standstill Then starting torque of an induction motor is given by 2 K1E2 R K1E2R 2 A. T B. T s 2 s 2 12 2 2 (R 2 2 X 2 ) ( R 2 2 X 2 ) K 2 E2 X 2 K1E2 X 2 C. Ts D. T s 2 2 12 2 2 (R 2 X 2 ) (R 2 X 2 ) A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 59 of 94 INDUCTION MOTORS 19. In a 3-phase induction motor, the torque A. increases with the increase in supply voltage B. decreases with the increase in supply voltage C. has no relation with the supply voltage D. A and B depending upon the situation 20. Improvement in the power factor in an induction motor A. decreases torque B. increases the torque C. increases the current D. increases the torque and decreases the current due to increased impedance 21. Torque in an induction motor under running condition is given by 2 2 K1 E 2 R 2 K1E2 R 2 B. T A. T R 2 SX 2 R 22 SX 22 2 2 K1SE2 R 2 K1SE2 R 2 C. T D. T R 22 ( SX 2 )2 R 22 X 22 22. In an induction motor the torque is related with the supply voltage as A. T V1 2 B. C. T α V2 D. TV 1 T V2 23. The maximum torque under running condition in terms of rotor reactance is given by KSE2 Kφ E 2 B. Tmax A. Tmax 2X 2 2X 2 C. 24. Torque A. B. C. D. Tmax KSE2 X2 2 D. Tmax KE2 2X 2 2 under running condition is maximum at the slip S which makes rotor reactance/phase equal to rotor resistance/phase which makes rotor reactance/phase greater than rotor resistance/phase which makes rotor reactance/phase lesser than rotor resistance/phase which is independent of rotor resistance 25. The value of slip at maximum torque condition (under running condition) in terms of R2 and X2 is R X B. S 2 A. S 2 X2 R2 2R 2 E C. S D. S 2 X2 2X 2 A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 60 of 94 INDUCTION MOTORS 26. Short circuit test on the induction motor can be used to find out A. the transformation ratio of the induction motor B. power scale of circle diagram C. copper losses in the induction motor D. all of the above 27. Which of the following is a correct relation for an induction motor? A. actual speed of rotor rotor efficiency synchronous speed B. rotor on losses = slip x rotor input C. rotor input = 2π x gross torque x synchronous speed D. all of the above relations are correct 28. Two of the power supply terminals to a 3-phase induction motor got interchanged during reconnection after maintenance of the motor, when put back into service, the motor will A. fail to rotate B. rotate in the same direction as it was prior to maintenance C. rotate in the reverse direction to that prior to maintenance D. stop 29. A 400 kW, 3-phase, 440 V, 50 Hz induction motor has a speed of 950 rpm on full load. The machine has 6 poles. The slip of the machine will be A. 0.06 B. 0.10 C. 0.04 D. 0.05 30. If the air gap of the induction motor is increased A. the magnetizing current will decrease B. the magnetizing current will increase C. the power factor will decrease D. none of the above is correct 31. In a slip-ring induction motor resistance is connected in rotor phases A. to limit starting current B. to increase the starting current C. to limit starting current and increase starting torque D. none of the above statement is correct 32. For a 3-phase, wound-rotor induction motor, as increase in rotor resistance affects the motor performance in the following way A. the starting current decreases B. the motor efficiency decreases C. the maximum torque is reduced D. the starting current decreases 33. It is advisable to avoid line starting of induction motor and use starter because A. starting torque is very high B. motor takes five to seven times its full load current C. it will pick-up very high speed and may go out of step D. it will run in reverse direction A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 61 of 94 INDUCTION MOTORS 34. A change of 5% in the supply voltage of a 3-phase induction motor will produce to its torque a change of approximately A. 5% B. 25% C. 10% D. 20% 35. A pump induction motor is switched on to a supply 30% lower than its rated voltage. The pump runs. What will eventually happen? It will A. start after some time B. continue to run at lower speed without damage C. get heated and consequently get damaged D. continue to run then stop after some time A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 62 of 94 ELECTRICAL MEASURING INSTRUMENTS 1. When using any instrument for measurement or testing an electrical circuit, your considered first A. personal safety B. theoretical knowledge C. surrounding D. dress should be 2. The resolution of an indicating instrument is A. the smallest change in the output reading due to drifting of pointer B. the smallest change in applied stimulus that will indicate a detectable change in deflection C. the difference between various readings for the same applied stimulus D. the difference between various readings for the difference applied stimulus 3. What should be the accuracy classes of industrial measuring instruments? A. Accuracy classes 1.0, 0.2 and 0.5 B. Accuracy classes 0.5, and 1 C. Accuracy classes 0.5, 1.0, 1.5, 2.5 and 5 D. Accuracy classes 1.0, 1.5, 2.5 and 5 4. What is A. B. C. D. the purpose of providing a mirror behind the pointer in measuring instruments? The scale is illuminated through the mirror With the help of the mirror it can be seen whether the pointer is bent or not The mirror is semi-transparent so as to allow the observation of the interior of the instrument Reading errors due to inclined observation are eliminated by removing parallax between the pointer and its image in the mirror 5. Which of the following statements about the internal resistance of measuring instruments is true? A. The internal resistance of ammeters should be very small and that of voltmeters very high B. The internal resistance of ammeters should be very high and that of voltmeters very small C. The internal resistance of ammeters and voltmeters should be very small D. The internal resistance of ammeters and voltmeters should be very high 6. Meter accuracy is determined by A. half-scale deflection C. one-fourth of full-scale deflection B. full-scale deflection D. one-tenth of full-scale deflection 7. The reliability of an instrument means A. the life of the instrument B. the extent which the characteristics remain linear C. degree to which repeatability continues to remain with specific limits D. all of these 8. Threshold of sensitivity with respect to instruments is A. the maximum signal which can be measured B. the value of sensitivity on the highest scale C. the value of sensitivity on the lowest scale D. the smallest signal that results in a detectable output A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 63 of 94 ELECTRICAL MEASURING INSTRUMENTS 9. Sensitivity inaccuracy of a recording instrument means A. the amount of input required to produce unit pen deflection B. the smallest signal required to produce detectable output C. the maximum error in sensitivity displayed by a pen D. degree to which the instrument is not sensitive enough to repeat readings 10. On which of the following factors the sensitivity inaccuracy of an instrument does not depend? A. hysteresis or dead bond B. amplitude distortion C. frequency response D. all of these 11. Damping provides A. braking action on a meter pointer C. starting torque on the meter pointer B. good accuracy D. counter torque to deflection torque 12. In moving-coil meters, damping is provided by A. the aluminum frame C. damping vane in an air tight chamber B. damping vane D. none of these 13. Moving coil instruments are used A. in ac circuits only C. in dc circuits only B. both in ac and dc circuits D. for measuring voltage only 14. To reduce the effect of a voltmeter upon the circuit under test, we should A. decrease the multiplier resistance B. get an instrument with a higher internal resistance C. use a parallel resistor D. use an ac meter with rectifier 15. To increase the range of a voltmeter A. a low resistance is connected in series B. a low resistance is connected in parallel C. a high resistance is connected in series D. a high resistance is connected in parallel 16. What is A. B. C. D. the function of the zero-adjust control in a multimeter? It serves to conduct the current. With this control, the sensitivity of the meter can be changed. The zero point is corrected with the help of this control. The moving parts can be tightened to the casing with the help of this control-screw 17. If moving-iron type ammeter is connected to a circuit, and we interchange its connection, then A. it will give no deflection B. its reading will not change C. it will deflect in the opposite direction D. it will burn out 18. Which of the following damping methods is common in moving coil instruments? A. air damping B. fluid damping C. spring damping D. eddy-current damping A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 64 of 94 ELECTRICAL MEASURING INSTRUMENTS 19. The main reason for using springs in a measuring instrument is A. to conduct the current to the coils B. to hold the pivot in position C. to control the pointer movement D. to minimize the vibration of the pointer 20. A moving-iron type instrument has A. a linear scale (uniform scale) B. a nonlinear scale C. its deflection directly proportional to the current D. its deflection directly proportional to the voltage 21. In moving-coil instruments, the scale used is A. nonlinear scale C. square law scale B. linear scale D. log scale 22. Two meters X and Y require 40 mA and 50 mA, respectively, to give full scale deflection, then A. X is more sensitive B. Y is more sensitive C. both are sensitive D. sensitivity cannot be judged with the given information 23. The function of a shunt in an ammeter is to A. bypass the current B. increase the current in the coil C. decrease the voltage drop D. increase the meter resistance 24. The shunt resistance in an ammeter is usually A. less than meter resistance B. equal to meter resistance C. greater than meter resistance D. of any value 25. External shunts are generally used for measuring currents greater than about A. 5 A B. 10 A C. 15 A D. 30 A 26. If the approximate value of the current to be measured is not known, measurement should start on A. the lowest range and then increase the range B. the highest range and then increase the range C. the middle range and then decrease the range D. the middle range and then increase the range 27. Sensitivity of a voltmeter is expressed as A. Volts/Ohm B. Ohms/Volt C. Ohms-Volt D. 1/Ohms Volt 28. A low voltage is measured on a higher scale of a voltmeter. The measurement would have A. low accuracy B. low resolution C. low precision D. all of these A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 65 of 94 ELECTRICAL MEASURING INSTRUMENTS 29. The disadvantage associated with an electrodynamic instrument is that A. it consumes more power B. it has low torque to weight ratio C. its frequency range is low D. all of these 30. An electrodynamic meter can be used to measure A. ac voltage B. dc voltage C. dc as well as ac voltage D. dc voltage but for ac voltages rectification is necessary 31. Megger is an instrument to measure A. very low resistance B. insulation resistance C. Q of a coil D. inductance of a coil 32. Megger essentially is a A. megohmmeter C. series-type ohmmeter B. shunt-type ohmmeter D. dynamometer 33. Megger in its operation is based upon A. moving-coil meter C. dynamic-meter meter B. moving-iron meter D. electrostatic meter 34. Which of the following equipment is not a part of megger? A. hand crank B. moving-coil meter C. a coil of high inductance D. gear box generator 35. The number of coils in the meter of megger is A. one C. three B. two D. four 36. With the measurement terminals open-circuited, the ‘infinity’ reading of megger is due to A. current in the coil is connected across the measurement points B. unit in the coil connected across the generator C. current in both the coils D. zero deflection of the pointer 37. A multimeter consists of A. voltmeter and ohmmeter B. voltmeter and current meter C. current meter and ohmmeter D. voltmeter, current meter and ohmmeter 38. A VTVM is more reliable as compared to multimeter for measuring the voltage across low impedance because A. its sensitivity is very high B. if offers high input impedance C. it does not alter the measured voltage D. all of these A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 66 of 94 ELECTRICAL MEASURING INSTRUMENTS 39. The simplest and most convenient form of detector used in a Wheatstone bridge for audio frequency range is A. galvanometer B. vibration galvanometer C. pair of headphones D. cathode ray tube indicator 40. Inductance is measured in terms of capacitance and resistance by A. Schering bridge B. Anderson bridge C. Maxwell-Wein bridge D. Wein bridge 41. Carey-Foster bridge is specially designed to determine. A. the high resistance of the wire B. the internal resistance of the battery C. the difference between two nearly equal resistances D. the emf of the voltage source 42. Schering bridge can be used to measure A. capacitance and its power factor B. Q of a coil C. inductance and its Q-value D. very small resistance 43. Which of the following bridges is used to measure inductance of the high Q-inductor? A. Maxwell bridge B. Hay bridge C. Wein bridge D. Anderson bridge 44. Which of the following bridge is used to measure inductance of a low Q-inductor? A. Maxwell bridge B. Hay bridge C. Wein bridge D. Anderson bridge 45. The potentiometer wire should have A. high specific resistance and high temperature coefficient B. high specific resistance and low temperature coefficient C. low specific resistance and high temperature coefficient D. low specific resistance and low temperature coefficient 46. Sensitivity of a potentiometer can be increased by A. decreasing the length of potentiometer wire B. increasing the length of potentiometer wire C. decreasing the current of potentiometer wire D. decreasing the resistance in the rheostat series with the battery 47. The cell is used in a potentiometer is A. a Dry cell C. a Leclanche cell B. a Daniel cell D. a Lead accumulator A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 67 of 94 ELECTRICAL MEASURING INSTRUMENTS 48. Induction type single-phase energy meter is A. an ampere-hour meter B. true watt-hour meter C. wattmeter D. none of these 49. A wattmeter can measure A. ac power only C. ac as well as dc power B. dc power only D. dc power and ac power after rectification A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 68 of 94 CIRCUIT BREAKERS 1. The function of protective relay in a circuit breaker is A. to earth any stray voltages B. to close the contacts when the actuating quantity predetermined value C. to limit arcing current during the operation of circuit breaker D. to provide additional safety in the operation of circuit breaker 2. Low voltage circuit breakers have rated voltages of less than A. 220 V B. 400 V C. 1000 V reaches a certain D. 10,000 V 3. A relay in which the measurement is performed by a stationary circuit and which has no moving parts is known as A. Static relay B. Differential relay C. Instantaneous relay D. Time relay 4. When a H.V. ac circuit breaker is tested for endurance, it is tested for at least A. 1000 opening-closing operations B. 100 opening-closing operations C. 10 opening-closing operations D. 5 opening-closing operations 5. For high voltage ac circuit breakers, the rated short circuit current is passed for A. 0.01 sec B. 0.1 sec C. 3 sec D. 30 sec 6. Which of the following is not a type of contactor for circuit breakers? A. electromagnetic B. electro-pneumatic C. pneumatic D. vacuum 7. Interrupting medium in a contactor may be A. air C. SF6 gas B. oil D. any of the above 8. In air blast circuit breakers, the pressure of air is of the order of A. 100 mg Hg B. 1 kg/cm2 2 C. 20 to 30 kg/cm D. 200 to 300 kg/cm2 9. SF6 gas A. B. C. D. is lighter than hydrogen is lighter than air has density 2 times as compared to that of air has density 5 times as compared to that of air 10. The pressure of SF6 gas in circuit breakers is of the order of A. 100 mg Hg B. 1 kg/cm2 2 C. 3 to 5 kg/cm D. 30 to 50 kg/cm2 11. While selecting a gas for circuit breaker, the property of gas that should be considered is A. high dielectric strength B. non-inflammability C. non-toxicity D. none of the above 12. Out of the following circuit breakers, which one has the lowest voltage range? A. air-break circuit breaker B. tank type oil circuit breaker C. Air-blast circuit breaker D. SF6 circuit breaker A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 69 of 94 CIRCUIT BREAKERS 13. Which of the following circuit breaker can be installed on 400 kV line A. Tank type coil circuit breaker B. Miniature circuit breaker C. Vacuum circuit breaker D. Air blast circuit breaker 14. In a HRC fuse the time between cut-off and final current zero, is known as A. total operating time B. arcing time C. pre-arcing time D. any of the above 15. Fusing factor for HRC fuse is A. Minimum fusing current Current rating C. Maximum fusing current Minimum rupturing time D. i nim um B. Minimum fusing current Minimum rupturing time fusing current Prospective current of a circuit 16. The insulation resistance of high voltage electric circuit breaker is A. 1 k B. 10 k C. 20 Mega ohms D. 2000 Mega ohms 17. There is definite objection to use of which of the following medium for extinguishing the arc in case of a circuit breaker? A. Air B. SF6 gas C. Vacuum D. Water 18. In a circuit breaker if the insulation resistance between phase terminal earthed frame is less than the specified limit, the probable cause could be A. moisture B. dirty insulation surface C. carbon or copper particle sticking to the internal surface D. any of the above 19. The transient voltage that appears across the contacts at the instant of arc extinction is called A. recovery voltage B. restriking voltage C. supply voltage D. peak voltage 20. In a circuit breaker the active recovery voltage depends upon A. power factor B. armature reaction C. circuit conditions D. all of the above A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 70 of 94 CIRCUIT BREAKERS 21. Best protection is provided by HRC fuse in case of A. Open circuits B. Short circuits C. Over loads D. None of the above 22. A fuse wire possesses A. inverse time characteristics B. direct time characteristics C. neither of the above 23. A relay used for protection of motors against overload is A. impedance relay B. Electromagnetic attraction type C. Thermal relay D. Buchholz’s relay 24. Fuse protection is used for current ratings up to A. 10 A B. 20 A C. 50 A 25. The fuse current in ampere is related with fuse wire diameter D as 1 C. 1 α D3 2 A. 1 B. 1 D D D. 100 A D. 1 D 2 26. A fuse wire should have A. low specific resistance and high melting point B. low specific resistance and low melting point C. high specific resistance and high melting point D. high specific resistance and low melting point 27. Fuse wire protection system is usually used beyond A. 10 A B. 25 A C. 50 A D. 100 A 28. For extra high voltage lines which circuit breaker is preferred A. Bulk oil circuit breaker B. Vacuum circuit breaker C. SF6 gas circuit breaker D. Minimum oil circuit breaker 29. The number of cycles in which a high speed circuit breaker can complete its operation is A. 3 to 8 B. 10 to 18 C. 20 to 30 D. 40 to 50 30. A material best suited for manufacturing of fuse wire is A. Aluminum B. Silver C. Lead D. Copper 31. In a circuit breaker, the current which exists at the instant of contact separation is known as A. restriking current B. surge current C. breaking current D. recovery current A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 71 of 94 CIRCUIT BREAKERS 32. A Merz-Price protection is suitable for A. transformers C. feeders B. alternators D. transmission lines 33. ‘Kick fuse’ has A. square law characteristics C. inverse characteristics B. linear characteristics D. direct characteristics 34. Air-blast breakers for 400 kV power systems are designed to operate in A. 50 microseconds B. 50 milliseconds C. 500 milliseconds D. 50 seconds 35. Breaking capacity of a circuit breaker is usually expressed in terms of A. amperes B. volts C. MW D. MVA 36. Which of the following equations correctly represents the relation between contact resistance r and the applied force F? k k B. F C. r A. F k.r D. r kFn r Fn 37. As the force on contact is increased, the contact resistance will A. increase linearly B. increase exponentially C. remain altered D. decrease 38. The heat produced at the contact point, due to passage of current, will least depend on B. contact resistance B. time during which the current flows C. current flowing D. temperature of the surrounding medium 39. Minimum arcing voltage for platinum is 16 V. It can be therefore concluded that when the voltage is below 16V C. it will not possible to interrupt the circuit D. it will possible to pass the current E. it will be possible to interrupt any value of current without arcing F. it will be possible to interrupt any value of current without bringing contact closer to another 40. Which of the following is not the method of arc dispersion? G. oil immersion contacts B. magnetic blow out of arc C. use of rectifiers D. deionization of arc path 41. Which of the following contact point metals has the highest melting point? A. Silver B. Tungsten C. Gold D. Copper 42. The arc voltage produced in the circuit breaker is always A. in phase with arc current B. leading the arc current by 90o C. lagging the arc current by 90o D. leading the arc current by 45o A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 72 of 94 CIRCUIT BREAKERS 43. Sparking between contacts can be reduced by H. inserting resistance line I. inserting a capacitor in series with the contacts J. inserting a capacitor in parallel with the contacts K. inserting an inductor in series with the contacts 44. For magnetic blow out of arc the magnetic field is produced L. in the load circuit M. parallel to the axis of the arc N. at right angle to the axis of the arc O. at 45 degrees with respect to the axis of the arc 45. Sparking occurs when a load is switched off because the circuit has P. high inductance B. high capacitance C. high resistance D. low resistance 46. For the same current, which of the following fuse wires will have the least fusing time? Q. 18 SWG TIN – 12.5 A B. 20 SWG TIN – 10 A C. 22 SWG TIN – 7.5 A D. 24 SWG TIN – 5 A 47. An automatic device that operates at present value is known as A. mercury switch B. relay C. fuse D. contactor 48. The basic function of a circuit breaker is to A. produce arc C. transmit voltage by arcing B. ionize the surrounding air D. extinguish the arc 49. The power factor of arc in the circuit breaker is A. always zero B. always unity C. always lagging D. always leading 50. Flame proof switch gears are usually preferred A. on transmission lines of low voltage C. in mines B. substations D. in high MVA capacity circuits 51. Air is used in air-blast circuit breaker A. must have least carbon dioxide C. must be free from moisture B. must be ionized D. none of these 52. In a circuit breaker the time duration from the instant of fault to the instant of energizing of the trip coil is known as A. lag time B. lead time C. protection time D. operation time 53. In a circuit breaker the time duration from the instant of the fault to the extinction of arc is known as A. operation time B. total clearing time C. lag time D. lead time 54. In a circuit breaker the time duration from the instant of fault to the instant of closing of contact is known as A. recycle time B. total time C. gross time D. reclosing time A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 73 of 94 CIRCUIT BREAKERS 55. For high speed circuit breaker the total clearing time is nearly A. 1 to 2 cycles B. 5 to 10 cycles C. 10 to 15 cycles D. less than 50 cycles 56. If the power is zero, the active recovery voltage will be A. minimum B. 0.5 C. 0.707 D. maximum 57. A circuit breaker will normally operate A. when the switch is put on B. when the line is to be checked C. when the power is to be supplied D. whenever fault in the line occurs 58. Which of the following circuit breaker will produce the least arc energy? A. minimum oil circuit breaker B. air blast circuit breaker C. plain oil circuit breaker D. all will produce the same energy 59. The breaking capacity of a circuit breaker in MVA ( 3 phase ) is given by A. rated service voltage x rated symmetrical current B. 1.1 x rated service voltage x rated symmetrical current 2 x rated service voltage x rated symmetrical current C. D. 3 x rated service voltage x rated symmetrical current 60. Which relay is used for feeders? A. MHO relay C. Merz-Price protection B. Translay relay D. Buchholz relay 61. Which of the following relays is used in transformers? A. Buchholz relay B. MHO relay C. Merz-Price relay D. None of the above 62. MHO relay is used for A. rectifier B. circuit breaker C. transmission lines D. feeders 63. Merz-Price protection is used on A. substations B. capacitor banks C. induction motors D. generators A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 74 of 94 CIRCUIT BREAKERS 64. The value of the fault current depend on A. voltage at the faulty point B. total impedance up to the fault C. both A and B D. none of the above 65. The advantage of the neutral earthing is A. simplified design of earth fault protection B. over-voltages due to the lightening can be discharges to the earth C. freedom from persistent arcing grounds D. all of the above 66. The over voltage surges in power system may be caused by A. lightening B. switching C. resonance D. any of the above 67. The protection against the over-voltage due to the lightning is provided by A. use of surge diverters B. low tower footing resistance C. use of overhead ground wires D. any of the above 68. Which of the following is a conducting medium for electric current? A. Low temperature gas B. High temperature gas C. Dissociated gas D. Plasma 69. In circuit breakers the contact space is ionized by A. thermal ionization of gas B. thermal emission from surface contacts C. field emission from the surface contacts D. any of the above 70. Which of the following are air-break switching devices? A. Isolator B. Limit switch C. Earthing switch D. All of the above 71. Which of the following is the deremit of SF6 circuit breakers? A. Sealing problem of gas B. In flux of moisture in the gas system is dangerous C. Deterioration of quality of circuit breaker affects reliability of circuit breakers D. All of the above A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 75 of 94 CIRCUIT BREAKERS 72. A fuse is normally a A. current limiting device B. voltage limiting device C. power limiting device D. power factor limiting device 73. Normally the fuse elements are in parts which are connected in the middle by tin bridge. The melting point of tin bridge is A. 35oC B. 88oC C. 230oC D. 540oC 74. The material used for bus bars should have A. low resistivity B. higher softening temperature C. low cost D. all of the above 75. Which of the following is not valid in case of aluminum as compared to copper? Aluminum is higher A. resistivity B. coefficient of linear expansion C. tensile strength D. joint resistance 76. Over current protection for motor is provided by A. cartridge fuses B. kit kat fuses C. over current relay D. all of the above 77. Fuse in motor circuits provides A. over current protection B. short-circuit protection C. open-circuit protection D. none of the above 78. In which method of starting a motor, the starting current is the maximum? A. Auto-transformer B. Star-delta transformer C. Stator rotor starter D. Direct-on-line 79. Over voltage transients may occur due to A. lightening B. switching C. arcing grounds D. any of the above 80. Switching surges may be caused by A. closing of the unchanged line B. load shedding or receiving end of line C. switching of magnetizing current D. any of the above A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 76 of 94 CIRCUIT BREAKERS 81. The disadvantages offered by underground system is A. frequent arcing grounds B. difficult earth fault relaying C. voltage oscillations D. all of the above 82. Solid grounding is used for voltages A. above 220 kV B. above 11 kV C. below 660 V D. below 115 V 83. Switching over voltages are more hazardous than lightening surges in case of A. low voltage systems B. 11 kV system C. unbalanced systems D. EHV and UHV systems 84. Current A. B. C. D. limiting reactors may be air cooled, air cored oil immersed magnetically shielded oil immersed non-magnetically shielded any of the above 85. Series reactors are installed at strategic locations of the power systems to A. bring down the fault level within the capacity of the switchgear B. directly pass the fault surges to ground C. pass the neutralizing surges of opposite nature D. discharge the capacitor A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 77 of 94 GENERATION OF ELECTRIC POWER 1. Which of the following generating stations has maximum running cost? A. thermal power station B. nuclear power station C. hydro power station D. none of these 2. Which of the following methods of generating electric power from the sea water is more advantageous? A. water power B. ocean power C. tidal power D. none of these 3. Out of the following, which one is not unconventional source of energy? A. tidal power B. geothermal power C. nuclear energy D. wind energy 4. Heating value of coal largely depends on A. ash content C. volatile matter B. moisture content D. size of coal particles 5. Power plants using coal work closely on which of the following cycle? A. Rankine cycle B. Binary vapor cycle C. Otto cycle D. Brayton cycle 6. The efficiency of a thermal power plant improves with A. increased quantity of coal burnt B. use of high steam pressures C. lower load in the plant D. larger quantity of water used 7. Which of the following contributes to improvement of efficiency of Rankine cycle in a thermal power plant? A. use of high pressures B. regeneration use of steam for heating boiler feed water C. reheating of steam at intermediate stage D. all of the above 8. Which of the following is not a high pressure boiler? A. Loeffer boiler B. Lancashire boiler C. Velox boiler D. La-Mount boiler 9. Overall thermal efficiency of a steam power station is in the range A. 18-24% B. 30-40% C. 44-62% D. 68-79% 10. In a steam turbine cycle, the lowest pressure occurs in A. turbine outlet B. boiler C. condenser D. superheater 11. Chemical composition of coal is given by A. Proximate analysis C. Orost analysis B. Ultimate analysis D. All of the above 12. For low head and high discharge, the hydraulic turbine used is A. Kaplan turbine B. Francis turbine C. Pelton wheel D. Jonval turbine A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 78 of 94 GENERATION OF ELECTRIC POWER 13. A graphical representation between discharge and time is known as A. Monograph B. Hectograph C. Hydrograph D. Topograph 14. A Pelton wheel is A. axial flow impulse turbine C. outward flow impulse turbine B. inward flow reaction turbine D. inward flow impulse turbine 15. A Francis turbine A. outward flow impulse turbine C. inward flow impulse turbine B. outward flow reaction turbine D. inward flow reaction turbine 16. Spouting velocity is A. 50% of ideal velocity of jet C. ideal velocity of jet B. actual velocity of jet D. velocity of jet under specified condition 17. A Kaplan turbine is A. a high head mixed flow turbine C. a reaction turbine, outward flow type B. an impulse turbine, inward flow type D. low head axial flow turbine 18. Outward radial flow turbines A. are impulses turbines B. are reaction turbines C. are partly impulse partly reaction turbines D. may be impulse or reaction turbines 19. In an impulse turbine A. always operates submerged C. is most suited for low head installation 20. A gas turbine works on A. Carnot cycle C. Dual cycle B. makes use of a draft tube D. operates by initial complete conversion to kinetic energy B. Brayton cycle D. Rankine cycle 21. Maximum efficiency of an open cycle gas turbine is nearly A. 40% B. 50% C. 60% D. 30% 22. Compressor used in gas turbine is A. screw compressor C. plunger type compressor B. multistage axial flow compressor D. reciprocating compressor 23. Overall efficiency of gas turbine is A. equal to Carnot cycle efficiency C. less than Diesel cycle efficiency B. equal to Rankine cycle efficiency D. more than Otto or Diesel cycle efficiency 24. The compressor ratio in case of diesel engine is A. 5 to 7 B. 7 to 10 C. 14 to 22 D. 25 to 36 A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 79 of 94 GENERATION OF ELECTRIC POWER 25. High horse power diesel engines are started by A. self starter B. cranking C. battery D. compressed air 26. Which of the following is a non-petroleum fuel? A. benzol B. methyl alcohol C. ethyl alcohol D. all of the above 27. Diesel engine fuels are rated by A. Octane number C. Cetane number B. H.U.C.R. D. CRF number 28. Air standard efficiency of a diesel engine depends on A. compression ratio B. speed C. fuel D. torque 29. Which engine has the highest air fuel ratio? A. Petrol engine C. Diesel engine B. Gas engine D. Gas turbine 30. Most of heat generated in internal combustion engine is lost in A. cooling water B. exhaust gases C. lubricating oil D. radiation 31. The internal combustion engines never work on A. Diesel cycle B. Rankine cycle C. Otto cycle D. Dual combustion cycle 32. The efficiency of thermal plant is approximately A. 10% B. 30% C. 60% D. 80% 33. Which of the following is not a secondary nuclear fuel? A. U-235 B. U-233 C. plutonium D. Pn-239 34. The function of moderator in nuclear reaction is A. to accelerate the reaction B. to control the reaction C. to absorb excessive neutrons D. to liberate excessive neutrons 35. Heavy water is A. H2O B. D20 36. Nuclear reactors generally employ A. fusion C. both fusion and fission C. W2O D. B2O B. fission D. none of the above 37. In water turbine, the runway speed of Pelton turbine is A. 1.8 times the rated speed B. 2 to 2.2 times the rated speed C. 2.5 to 2.8 times the rated speed D. 3 to 4 times the rated speed A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 80 of 94 ECONOMICS OF POWER GENERATION 1. Load factor during a period is A. Average load Maximum Load Average load C. Installed capacity 2. B. D. Maximum load Installed capacity Maximum load Average Load For economy in generation power A. load factor should be high B. diversity factor should be high C. plant utilization factor should be high D. load factor and diversity factor should be low 3. A load curve is a plot of A. load versus time C. load versus current B. load versus cost of power D. load versus generation capacity 4. During which season the load on a power plant supplying power to a city will be highest? A. rainy season B. summer C. winter D. autumn 5. During summer months the increased load is due to A. increased water supply B. vacations in institutions C. increased business activities D. increase used of fans and air conditioners 6. Load due to a ceiling fan is nearly A. 40 to 50 W C. 250 to 2000 W B. 10 W D. 100 to 200 W 7. Which domestic utility item has highest power rating? A. electric iron B. ceiling fan C. mixi D. refrigerator 8. A power plant supplying energy to a city will usually experience peak demand A. from midnight to early morning B. 8 AM to 12 noon C. 2 PM to 6 PM D. 6 PM to 12 PM Maximum demand of the installation is known as Sum of individual maximum demand A. demand factor B. plant use factor C. diversity factor D. plant capacity factor 9. The ratio 10. Capital cost per MWh is the highest in case of A. steam power plant C. nuclear power plant B. diesel engine power plants D. hydroelectric power plant 11. A diesel power plant is best suited as A. standby plant C. peak load plant B. base load plant D. general purpose plant A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 81 of 94 ECONOMICS OF POWER GENERATION 12. A gas turbine power plant usually suits for A. peak load operation C. casual run B. base load operation D. none of the above 13. Which power plant cannot have single unit of 100 MW? A. hydroelectric power plant B. diesel power plant C. steam power plant D. nuclear power plant 14. The useful life of a diesel engine in a power plant is expected to be A. five years B. one year C. fifty years D. fifteen years 15. Which of the following plants is expected to have the longest expected life? A. steam B. hydroelectric C. diesel D. all have equal life 16. For a power plant the expenditure on which of the following items is expected to be negligible? A. publicity B. taxes B. wages D. insurance 17. At break-even point A. constant expenses = profits C. total sales = total expenses B. total sales = variable expenses D. variable expenses – profits = total sales 18. A nuclear power plant is invariably used as a A. base load plant C. standby plant B. peak load plant D. spinning reverse plant 19. Efficiency is secondary consideration in case of A. base load plants C. peak load plants B. both peak load and base load plants D. none of the above 20. Which of the following plants will take least time in starting from cold conditions to full load operation? A. gas turbine B. steam power plant C. nuclear power plant D. hydroelectric power plant 21. During load shedding A. system voltage is reduced C. system power factor is changed B. some loads are switched off D. system frequency is reduced 22. Which statement about the daily load curve is valid? A. The area under the curve gives the average demand. B. The ratio of the area under the curves to the total area of rectangle in which it is contained gives the load factor for the day. C. The peak of the curve gives the installed capacity of the plant. D. The area of the curve divided by the number of houses gives load factor A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 82 of 94 ECONOMICS OF POWER GENERATION 23. An equipment purchased for $10,000 two years ago has a market value of $1,250 at present. It can be concluded that A. The value has depreciated according to straight-line method. B. The value has depreciated according to diminishing value method. C. The value has depreciated according to sinking fund method. D. The value has depreciated with time. 24. In a steam power plant, which component needs maximum maintenance attention? A. boiler B. condenser C. turbine D. water treatment plant 25. A certain plant has fixed cost of $40,000 and a salvage value of $4,000 at the end of a useful life of 20 years. The depreciated value of the plant at the end of 10 years will be least (interest rate being 6% compounded annually) when calculated by A. Diminishing value method B. Sinking fund method C. Straight-line method D. Sum-of-years digits method 26. In problem 25, the value will be highest when calculated by A Straight-line method B. Diminishing value method C. Sinking fund method D. Sum-of-years digits method 27. When a power plant is not be able to meet the demand of consumers it will resort to A. load shedding B. efficient plant operation C. power factor improvement at the generators D. penalizing high load consumers by increasing the charges of electricity 28. Load shedding is possible through A. switching off the loads C. voltage reduction B. frequency reduction D. any of the above 29. Ideally depreciated value of the plant plus the accumulation is the depreciation fund should be equal to A. sinking fund B. original invested capital C. salvage value D. obsolescence rate 30. In power plant, insurance cover is provided for A. equipment only C. unskilled workers only B. skilled workers only D. all of the above 31. Which of the following relation is incorrect? A. Capacity factor = Utilization factor x Load factor B. Load factor x Maximum load = Average load C. Demand factor x Connected load = Maximum demand D. None of the above 32. Sinking A. B. C. D. fund is Initial value – Salvage value Capital cost – Operating cost Periodical maintenance – Breakdown maintenance Capital cost USeful life A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 83 of 94 ECONOMICS OF POWER GENERATION 33. A low utilization factor for a plant indicates that A. plant is used for base load only B. plant is under maintenance C. plant is used for standby purpose only D. plant is used fro peak load as well as base load A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 84 of 94 TRANSMISSION AND DISTRIBUTION 1. Which of the following is usually not the generating voltage? A. 11 kV B. 13.2 kV C. 9.9 kV D. 6.6 kV 2. The fact that a conductor carries more current on the surface as compared to core is known as A. corona B. permeability C. unsymmetrical fault D. skin effect 3. Transmission efficiency increases as A. voltage and power factor both decrease B. voltage and power factor both increase C. voltage increases but power factor decreases D. voltage decreases but power factor increases 4. Skin effect is proportional to A. (diameter of conductor)2 C. (diameter of conductor)3 B. diameter of conductor D. (diameter of conductor)1/2 5. The surge impedance for overhead line is taken as A. 50-60 ohms B. 1000-2000 ohms C. 10-20 ohms D. 100-200 ohms 6. The effect of corona is A. increased reactance C. increased energy loss B. increased inductance D. all of the above 7. The current drawn by the line due to corona losses is A. non-sinusoidal B. sinusoidal C. square D. triangular 8. Presence of ozone as a result of corona is harmful because A. it gives bad odor B. it transfers energy to the ground C. reduces the power factor D. it corrodes the material 9. For 66 kV lines, the number of insulator discs used is A. 8 B. 12 C. 5 D. 3 10. Wooden poles for supporting transmission lines are used for voltages up to A. 22 kV B. 440 kV C. 11 kV D. 66 kV 11. The surge impedance of transmission lines is about A. 100 ohms B. 250 ohms C. 500 ohms D. 50 ohms 12. For transmission lines, the standing wave ratio is the ratio of A. maximum current to minimum voltage B. maximum voltage to minimum voltage C. maximum reactance to minimum reactance D. peak voltage to rms voltage 13. For a distortionless transmission line (G = shunt conductance between two wires) A. RL = GC B. RG = LC C. RLGC = 0 D. R G L C A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 85 of 94 TRANSMISSION AND DISTRIBUTION 14. A relay used in long transmission line is A. reactance relay C. mho’s relay B. impedance relay D. no relay is used 15. The power transmitted will be maximum when A. sending end voltage is more C. reactance is high B. receiving end voltage is more D. corona losses are least 16. Surge impedance of transmission line is given by C A. B. L 1 C. D. CL 17. Stages A. B. C. D. CL L C in the provision of electrical energy to a consumer are: generation and transmission generation, distribution and transmission generation, dissipation and distribution generation, transmission and distribution 18. The purpose of a grid system is to A. interconnect the power stations B. supply energy to remote areas C. make extra high voltage available to consumers D. make distribution of energy at reasonable cost 19. Line loss of a transmission line for a given power is A. directly proportional to supply voltage and power factor B. inversely proportional to supply voltage and power factor C. directly proportional to supply voltage and inversely proportional to power factor D. directly proportional to power factor and inversely proportional to supply voltage 20. The volume of copper required for a transmission line to transmit a given power is A. directly proportional to supply voltage and power factor B. inversely proportional to supply voltage and power factor C. directly proportional to supply voltage and inversely proportional to power factor D. directly proportional to power factor and inversely proportional to supply voltage 21. For a given current density, the resistance voltage drop per line is A. constant B. increase with voltage increase C. increase with voltage decrease D. remain constant for all voltages 22. The percentage voltage drop of transmission line of question 21 will A. increase with voltage increase B. decrease with voltage increase C. increase with voltage decrease D. remain constant for all voltages A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 86 of 94 TRANSMISSION AND DISTRIBUTION 23. The efficiency of transmission for a given power improves as A. voltage increase and power factor decreases B. voltage decreases and power increases C. voltage and power factor increase D. voltage and power factor decrease 24. Extra high voltages are needed for long distance transmission, transmitting a given power to reduce the A. current and cross-sectional area of the line B. current and the voltage drop C. voltage drop and cross-sectional area of the line D. power factor and the voltage drop 25. Various dc and ac systems of transmission are available but to find out which system is superior, comparison is made on the basis of equal A. rms voltage between the conductors B. rms voltage between the conductor and earth C. maximum voltage between conductors D. maximum voltage between the conductor and earth 26. Comparison of various overhead transmission systems is made with the A. rms voltage between the conductors B. rms voltage between the conductor and earth C. maximum voltage between conductors D. maximum voltage between the conductor and earth 27. For underground cable systems, the comparison is made with the A. rms voltage between the conductors B. rms voltage between the conductor and earth C. maximum voltage between conductors D. maximum voltage between the conductor and earth 28. For ac transmission, whether overhead or underground, the most unsuitable system is the A. 3-phase, 3-wire B. 3-phase, 4-wire C. single phase D. 2-phase, 3-wire 29. Among A. B. C. D. all the ac systems, the most superior system is 3-phase, 3-wire with maximum voltage between conductors 3-phase, 3-wire with maximum voltage between conductor and earth 3-phase, 3-wire with rms voltage between conductors 3-phase, 3-wire with rms voltage between conductor and earth 30. For overhead transmission line, 3-phase, 3-wire system is A. superior over single phase, 2-wire midpoint earthed system B. superior over 2-phase, 4-wire system C. not superior over the other two D. not used in practice A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 87 of 94 TRANSMISSION AND DISTRIBUTION 31. The greatest economy of conductor material is possible by adopting a dc system for transmission, particularly when the power factor of the ac system is considerably less than unity. The factor which limits the dc transmission is A. no easy way of obtaining high voltage B. high voltage drop C. that dc resistance is higher than ac resistance D. that rms voltage is not available 32. The problems associated with ac transmission system are A. high voltage drop, insulation and instability for long lines B. continuous loss even at no load, insulation and instability for long lines C. continuous load due to charging current, high voltage drop and instability for long lines D. continuous loss due to charging current, high voltage drop and insulation 33. The behavior of an ac transmission line used for power transmission depends upon A. alternating electrostatic field, resistance and length of the line B. alternating electrostatic field, alternating electromagnetic field and length of the line C. alternating electromagnetic field, resistance and length of the line D. resistance, alternating electrostatic field and alternating electromagnetic field 34. Short transmission lines have a length not exceeding A. 40 kilometers B. 20 kilometers C. 80 kilometers D. 100 kilometers 35. One of the line parameter which is neglected in short transmission line is A. capacitance B. inductance C. resistance D. admittance 36. For a receiving end current I and lagging power factor angle Ψ, the sending end voltage Vs for a short transmission line is A. Vs = Vr + IX cos Ψ + IR sin Ψ B. Vs = Vr – IX cos Ψ + IR sin Ψ C. Vs = Vr – IR sin Ψ + IX cos Ψ D. Vs = Vr – IR cos Ψ + IX sin Ψ 37. The term includes the use of cable and associated control and protective equipment necessary for supplying electrical energy to required positions on consumer’s premises A. generation B. transmission C. distribution D. generation and distribution 38. A low tension distribution system consists of A. transmission lines, transformers and circuit branches B. feeders, distribution and service mains C. feeders, transformers and distributors D. transmission line, distributors and circuit breakers 39. A feeder in a distribution system is designed primarily from the point of view of A. voltage drop B. current carrying capacity C. voltage drop and current carrying capacity D. load capacity A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 88 of 94 TRANSMISSION AND DISTRIBUTION 40. The supply undertaking is allowed to vary the actual voltage at the consumers terminal A. because ac supply alternates during each cycle B. because of the voltage drop along the distributor C. owing to large load at the consumer end D. owing to variation of power factor along the distributor 41. The consumer main switch gear is usually located A. in the center of the house B. out of reach C. over the kitchen sink D. at the intake position 42. For the same amount of power to be delivered to a consumer, if the supply voltage is increased to n times, the size of the feeder cable is 1 times B. increased to n times A. reduced to n 1 C. reduced to times D. increased to n – 1 times n 1 43. If the voltage of a distribution cable is increased to n times, then for the same power and percentage voltage drop new resistance R of the same length of the distribution in terms of the old resistance R will be A. R1 = R/n2 B. R1 = n2R C. R1 = R/n D. R1 = nR 44. The weight of the copper required for the new distributor of question 42 will be A. increased to n2 times B. increased to n times C. reduced to n times D. reduced to 1/n2 times 45. In spite of the advantages of increasing voltage for distribution, the limiting factors are: A. disproportionately greater cost of higher voltage cables and supplied to a consumer must be at consumer voltage B. voltage drop and the cost of higher voltage cable C. the power loss and cost of the higher voltage cable D. the power loss and voltage drop 46. A 3-wire dc system of distribution is preferred to a 2-wire dc system because it A. results in a saving of copper and has less resistance B. results in a saving of copper and makes two alternative voltage available C. has less resistance and results in less voltage drop D. makes two alternative voltage available and results in less voltage drop 47. The two types of distribution systems used are A. radial and delta C. ring main and radial B. radial and star D. ring main and delta 48. The advantage of the ring main system is A. less voltage drop in the feeders C. less costly B. continuity of supply to feeding points D. none of the above A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 89 of 94 TRANSMISSION AND DISTRIBUTION 49. To reduce the voltage drop at a particular feeding point or load, the system preferred is A. ring main B. radial C. interconnected D. radial arrangement superimposed 50. For a given loading, it is better to feed radial distributor at both ends as this gives A. minimum loss and voltage drop B. greater cross-sectional area of the conductor and minimum loss C. continuity of supply and greater cross-sectional area of the conductor D. greater cross-sectional area of the conductor and minimum voltage drop 51. For a 3 wire d.c. distributor fed at one end, if the total voltage drop in the neutral is positive it is A. added to the negative drop B. deducted from the positive drop C. added to the positive drop and deducted from the negative drop D. deducted from the positive drop and added to the negative drop 52. With point loads in a distributor fed at both ends, in order to determine the maximum voltages drop it is necessary to know the point of A. largest load B. minimum voltage C. maximum voltage D. least load 53. At the point of the minimum potential in a distributor fed from both ends, the load at the point is A. supplied from the left hand feeding point B. supplied from the right hand feeding point C. supplied from the left and right hand feeding points D. minimal 54. To determine the distribution of load at the point of the minimum potential, the moments in ampere meters about the one of the feeding point the moments in ampere meters about the other feeding point, A. should be less than B. should be greater than C. could be equal to D. must be equal to 55. For a.c. distributors, the power factor of the load has to be taken into consideration and the calculations became cumbersome. The approximate method that gives results with in plus or minus 5 percent of the actual voltage drop involves calculating A. the center of gravity of the load and average power factor B. the center of gravity of the load, the point of minimum potential and average power factor C. the center gravity of the load, resistance and reactance per double run and average power factor D. the average power factor, the point of minimum potential and resistance and reactance per double run 56. Voltage drop in a uniformly loaded distributor fed at one end is calculated by assuming the whole of the load concentrated at A. middle point B. feeding point C. the far end of the feeding point D. distance from the feeding point A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 90 of 94 TRANSMISSION AND DISTRIBUTION 57. Uniformly loaded distributor fed at equal potentials from both ends is treated like the distributor of question 37 because the voltage drop is A. approximately halved B. exactly halved C. equal to the two feeding points D. different at the feeding points 58. In actual practice, the potential at the two feeding points is unequal. To calculate the voltage drop, the difference in potential is A. added to the actual voltage drop B. subtracted from the actual voltage drop C. converted into ampere meters and added to the moments of the higher feeding point D. converted into ampere meters and moments of the lower feeding point start from this initial value 59. There should be no break in the neutral, which is usually earthed at the supply end, of a 2 wire a.c. distribution system because A. it would make all part dead B. excess current protection would be affected C. the action of switching will be nullified D. it would affect the voltage 60. Commercial premises usually but some domestic installations have 3 phase, 4 wire distribution system because A. the supply tariff is cheaper B. there services are cheaper to install C. the load is relatively large D. the voltage drop is less 61. The economical section of the feeder can be obtained by applying A. Ohm’s law B. Faraday’s law c. Lenz’s law D. Kelvin’s law A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 91 of 94 ILLUMINATION 1. The study of illumination involves A. design of lighting system B. study of lighting and wiring system C. calculations of wiring sizes for various lighting fixtures D. study of photometry and its application 2. Energy A. B. C. D. radiated continuously in the form of lighting waves is called luminous intensity lumen luminous flux illumination 3. The luminous flux emitted in unit solid angle by a uniform point source having a luminous intensity of 1 candela is called A. lumen B. lux C. illumination D. luminance 4. The luminous intensity is defined as A. Lumen per square meter B. Luminous flux per unit solid angle C. Illumination per square meter D. Candela per unit solid angle 5. The luminous intensity of the lamp is expressed in A. watts B. lumens C. lux D. candela 6. The illumination at the point of the surface is the luminous flux per unit area of the surface and its unit is A. lux B. lumen C. candela D. candela power 7. Polar curve of a filament lamp A. shows the distribution of illumination in all directions B. shows the luminous intensity in all directions in one plane around a light source C. determine the efficiency of the lamp D. gives the effectiveness of the reflector used for a lamp 8. When the light distribution from a lamp or a lamp and fitting is non-uniform the correct value of the luminous intensity in the particular direction is A. give the inverse law B. given the sine law C. given by the average value D. taken from the polar curve 9. The illumination of a surface is A. directly proportional to the distance of the source B. inversely proportional to the distance of the source C. directly proportional to the square of the distance of the source D. inversely proportional to the square of its distance from the source A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 92 of 94 ILLUMINATION 10. The illumination of a surface at any point is proportional to the normal at that point and the direction of the luminous flux. A. sine B. cosine C. tangent of the angle between the D. cotangent 11. The first object of a lighting system is to provide adequate illumination on the working surface. For proper design the effects of the surroundings must be taken into account and the factors are A. finish of windows, proportions of room and temperature B. finish of ceiling and walls, proportion of room, and place of work C. color of ceiling and walls, proportion of room and window space D. height of light fittings, room temperature and color of ceiling and walls 12. To use A. B. C. D. lumen method of design, you must first find room index and the lumens room index and then coefficient of utilization light distribution from a polar curve and then coefficient of utilization coefficient of utilization and then room index 13. Maintenance factor or depreciation factor takes account of A. effects of duct, dirt and fall in light output of the lamp during its life B. depreciation in capital cost of installation C. effects of dust, dirt and the type of lamp used D. condition of the room and the type of lamp used 14. Typical values of maintenance factors range about for good maintenance conditions down to for dirty conditions with poor maintenance and cleaning. A. 0.9, 0.6 B. 0.8, 0.6 C. 0.6, 0.5 D. 0.8, 0.4 15. Total lumens output from lamps when new is equal to A. total lumens required x coefficient of utilization maintenance factor B. coefficient of utilization x maintenance factor total lumens required C. total lumens required x maintenance factor coefficient of utilization D. total lumens required maintenance factor x coefficient of utilization 16. Another requirement of a good lighting scheme is that it makes the principal object the brightest thing in the field of vision. An illumination ratio of 10 : 3 : 1 has been suggested as the best for A. background/task/surroundings B. task/background/surroundings C. background/surroundings/task D. surroundings/background/task 17. The lumen output of a 230-volt, 100 watts gas field lamp is approximately A. 700 B. 1000 C. 1200 D. 1500 18. The principle of working of a high pressure mercury vapour lamp is that A. the radiation from the discharge excites a fluorescent material B. the radiation is produced directly by the discharge C. the radiation is produced by the argon gas D. very high voltage is needed to start the discharge A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 93 of 94 ILLUMINATION 19. Although the average efficiency of a 400 watts high pressure mercury vapour lamp is high but its main disadvantages are A. high cost, color distortion and high copper loss B. color distortion, stroboscopic effect and cannot be started immediately C. high cost, cannot be started immediately and high copper loss D. needs a capacitor, a choking coil and a starter 20. Low pressure in a fluorescent tube is obtained by A. high starting voltage B. high current density C. low current density D. low starting voltage A_Compilation_of_Objective_Type_Questions_in_Electrical_Engineering 94 of 94
