1. Give the physical significance of the following electrical quantities.
(i)
Voltage
(ii)
Current
(iii)
Resistance
(iv)
Inductance
(v)
Capacitance
2. What is the difference between active power, reactive power and apparent power? Give an
example to justify the answer.
3. What do you mean by power factor?
4. Why electrical generation companies prefer improved power factor?
5. Why ac systems are preferred over dc systems?
6. Explain Faraday’s law of electromagnetic induction.
7. Explain KCL and KVL. Give an application also.
8. What is the difference between Induction motor and transformer?
9. What is the difference between induction motor and synchronous motor?
10. What are the methods to improve power factor.
11. How synchronous machine is used to improve the power factor?
12. What are the applications of dc motors (series, shunt and compound)?
13. What is the relation between ac resistance and dc resistance? Which one is greater?
14. Why transformer rating is always given in VA?
15. What is Ferranti effect?
16. What is skin effect?
17. When will the bundled conductors are used in overhead transmission line?
18. What do you mean by “right of way” in case of an overhead line?
19. What is the physical significance of holding and latching current?
20. Why high voltage transmission is done?
21. Why generating voltage is upto 11kV?
22. Why negative feedback is preferred in control systems?
23. Why thyristor is considered as charge controlled device?
24. What is armature reaction in case of a dc machine?
25. What is the main difference between UPS and Inverter?
26. What are the different losses in case of induction motor?
27. Plot a graph showing e-5sin100t and e-5sin50t on the same plot.
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Plot a graph showing e sin100t and e sin100t on the same plot.
What are the conditions of parallel operation of an alternator?
What are the different types of hydro turbine
What is the difference between conduction, convection and radiation?
What are the advantages of HVDC transmission live?
What are the different types of torque in case of electrical measuring meters?
What is controlling torque in case of electrical measuring meters?
What is damping torque in case of electrical measuring meters?
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What is the physical significance of back emf in case of dc motor?
What is the physical significance of counter torque in case of dc generator?
Give difference between isolators and circuit breakers.
Why single-phase induction motor has no inherent starting torque?
Explain Thevenin’s Theorem.
Why star –delta conversion is done?
What is the difference between synchronous generator and asynchronous generator?
What is AC voltage controller? Give its application.
Why capacitors are used in ac only?
What is form factor and peak factor?
What is meant by cycle in ac waveform? What is period? Define frequency?
How electrons and holes contribute in flow of current in semiconductor?
What do you mean by ripple factor in case of diode rectifier?
What is transformer utility factor?
What is the difference between ground, neutral and earth?
What is settling time in case of time domain analysis of 2nd order control system?
Why transistor gives 1800 phase shift?
How stepper motor works?
What is the difference between auto- transformer and normal transformer?
Which source of energy is used to generate maximum electricity in India?
What is distributed generation?
Why secondary of CT is kept short circuited?
What is the difference between measuring CT and protective CT?
How a SCR gets protected?
What is Snubber circuit?
What is the difference between GTO and SCR?
What are the starting methods of induction motor? Give application also.
What is difference between permeability and permittivity?
What is difference between insulator and dielectric?
How corona occurs in case of overhead lines?
Which relay is preferred for transformer protection?
What is the advantage of static relay over electromagnetic relay?
What is the physical significance of mmf and emf?
What is BH curve?
What do you mean by magnetic saturation?
Which bridge is used to measure frequency of electrical supply?
What is the application of megger?
Which bridge is used to measure mutual inductance?
Why Schering bridge is used in electrical measurement?
What do you mean by synchronous speed?
What are the advantages of speed control using thyristors?
What is the basic working of circuit breaker and relay?
78. Two bulbs of 100W and 40W respectively are connected in series across 230V supply. Which
bulb will glow bright and why?
79. What is the advantage of using freewheeling diode in full wave rectifiers?
80. What is the full form of KVAr?
81. What is the difference between induced draft and forced draft fan in thermal power plants?
82. What is the use of electrostatic precipitator in thermal power plants?
83. Why 3 point starter is used in DC motors?
84. What is the difference between 3-point and 4-point starter?
85. Why synchronous machine is used for production of electricity?
86. Why series motor cannot be started on no load?
87. Mention the methods of starting of 1- phase induction motor?
88. What is ASCR cable and where we use it?
89. What will happen when power factor is leading in power system?
90. What is meant by impedance diagram?
91. What is difference between network synthesis and network analysis?
92. What is the role of speed governor in case of generators?
93. Why field winding is placed on rotor in case of synchronous machine?
94. What is Hall effect? Give an application.
95. Give example of pentavalent and trivalent impurities in case of semi conductor.
96. What are the advantages of EHV transmission?
97. Describe the function of line insulators.
98. What is slip in case of induction motors?
99. What are the demerits of low power factor?
100.Why is the starting current high in dc motor?