5.
6.
2.
3.
4.
1
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY
HYDERABAD
I YEAR B.TECH. I st MID TERM EXAMINATION
NETWORK ANALYSIS – 07A1EC05
UNIT-I
1. Explain the following terms. a) Electric circuit c) Resistance b) Electrical Potential
d) Temperature coefficient of resistance and it’s units
State and explain ohm’s law. What are it’s limitations?
Explain the effect of temperature on resistance of i) Metals b) Alloys
Derive expression for Y ∆ transformation or star connection of three resistances
Derive expression for resistances
∆ c) Electrolytes d) Insulators
- Y transformation or delta connection of three equivalent
[5M]
[5M]
[5M]
Explain different types of independent, dependent sources? [5M]
Contd…2

8.
2
Ω resistor. [5M]
9. Find the equivalent resistance across x-y terminals. [5M]
10. Determine the value of r in the given circuit [5M]
Contd…3

11. Find
2
3
[5M]
12. For the circuit shown find drop across r
2
13. If the power loss in 1 resistor is 25w, find the value of K? [5M]
Contd…4

4
14. Find the current through r
L
[5M]
15. Find the value of R when power supplied by both the sources is equal to each other. [5M]
16. Determine the resistance between the terminals of the network shown. [5M]
Contd…5

5
17. Determine the resistance between the terminals A and B if the resistance of each branch is 6 given
18. Solve the given network and obtain the potentials of the points a b & c? [5M]
Contd…6

6
19. For the following circuit obtain V
A
, V
B
and V c
? [5M]
20. A coil has a resistance of 25 Ω at 15 o resistance at 15 o
C. If the temperature coefficient of
C is 0.004/k, determine the resistance of the coil at 80 o C. [5M]
21. Compare the diameter of an aluminum conductor with that of a copper conductor for the same length and resistance of conductors. The resistivities of aluminium and copper are 0.0284/4 Ω m and 0.0178 µ Ω m respectively. [5M]
22. A conductor has a resistance of 1.5
Ω . What is the resistance of a conductor of the same material which has half the diameter and three times it’s length. [5M]
23. The resistance of a transformer winding is 2.5
Ω at room temperature of 18 o C.
After shours of full load operation the resistance of the winding is measured to be
3.0 find the rise in temperature of the winding. Take α o
= 0.004 / K
24. The lamp filament has a resistance of 27 Ω at 20 o C. Determine the resistance of the filaments at the operating temperature of 2000 o C. The temperature coefficient of resistance of the filament material is 0.005/K at 0 o
Contd…7
25. In the circuit shown calculate the current battery and in the load. [5M]

7
26. In the given bridge network calculate the current through 20 Ω resistor? [5M]
27. Find the input resistance at AB for the lattice network shown? When CD is short circuited. [5M]
Contd…8

8
28. Find the input resistance at AB for the lattice network shown when CD is open circuited. [5M]
29. Determine currents thought each branch? [5M] voltage AB. [5M]
Contd…9

9
31. Obtain the potentials of A in the given network using nodal analysis? [5M]
32. Using source conversion technique to find the current I in the circuit? [5M]
33. Find the voltage drop across 1 Ω resistor? [5M]
34. Convert the following circuits into a single voltage source. [5M]
Contd…10

10
35. What is the power supplied by the dependent source in the given circuit [5M]
36. Using mesh analysis find the current flow through 50 source. [5M]
37. Find power supplied by 10V in the given network. [5M]
38. Find the voltage across the 2A source with polarities as shown. [5M]
Contd…11

11
39. Find the voltage drop across the terminals a-e [5M]
40. Find
2 the network? [5M]
^*^*^

1.
12
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY
HYDERABAD
I YEAR B.TECH. I st MIDE TERM EXAMINATION
SUB: NETWORK ANALYSIS-07A1EC05
UNIT-II
Obtain the effective value of the periodic waveform given figure below? [5M]
2. Obtain the r.m.s value of the given periodic current wave form shown in figure.
[5M]
3. A sinusoidal alternating current has a maximum value of 10A. Find the instantaneous value at i) 1/12 cycle ii) 1/6 cycle iii)
5
8 cycle iv)
4
cycle. [5M]
Contd…2

13
4. A current has the following steady state values in ampres for equal intervals of time as shown in figure below. Obtain peak factor, average value. [5M]
5. Obtain the average value of the following waveform shown in figure. [5M]
7.
6. Write short note on: i) average ii) rms value iii) peak factor iv) formfactor [5M]
Find the average, rms value of trapezoidal voltage wave shown below in figure.
[5M]
Contd…3

14
8. Find rms, average value of the waveform shown. [5M]
9.
10.
Calculate the rms value of the current given by I=10+5cos (628t+30 o ) [5M]
Find the average, rms values of the current I(t) = 10+10 sin 3/ut. [5M]
11. A parallel circuit consists of two branches, one consisting of resistance 5 and inductance 38.2 mH, the other non inductive resistance 16
Ω
Ω in series with a capacitor of 300 µ f capacitance. The circuit connected to a 230V, 50Hz supply
Determine i) current in each branch ii) Total current. [5M]
12. A resistance of 30 Ω is connected in series with a 120 µ F capacitor across a
230V, 50Hz supply. Determine current through the circuit, phase difference
13. The voltage across and current through a circuit are given by υ =250 sin(314t-10 o )V I=10sin (314t+50 o )A calculate impedance, resistance, reactance of circuit. [5M]
14. A coil of resistance 10 Ω and inductance 0.02H is connected in series with another coil of resistance 6 Ω and inductance 15mH across 230V, 50Hz supply.
Calculate i) impedance of the circuit
15. An impedance of 10 ∠ 50 o ii) the voltage drop across each coil
is connected in series with another impedance of
[5M]
15 ∠ − 45 o Ω and combination takes a current of 2A. Calculate the voltage across
16. Three impedances z
1
, z
2
, z
3
are connected in series with across a 230V, 50Hz supply. If z
1
=10 Ω , z
2
=8+j10 Ω z
i) current through the circuit
3
=15-j15 Ω . Determine:
ii)the power factor voltage each
Contd…4

15
17. A parallel circuit consists of two branches, one of a non inductive resistance of
300 Ω in series capacitor of 0.01
µ f capacitance. The circuit is connect across
25V, 100KHz supply. Determine current through each branch. [5M]
18. Two inductive coils A and B are in parallel across a 100V, 50Hz supply. Coil A takes 12 A at 0.9 power factor and total current for both the coils is 20A at 0.8 power factor. Determine equivalent circuit resistance and reactance. [5M]
19. Single phase circuit consists of three parallel branches the admittances of the branches are Y
1
=0.4+j 0.6, Y
2
= 0.1+j 0.42, Y
3
= 0.06+j0.23.
Determine the total admittance and impedance of the circuit? [5M]
20 Determine (i) currents I
1
,I
2
,I
3
and I [5M]
21 Determine the currents I
1
, I
2
, I
3
and I [5M]
Contd…5

16
22. Determine total impedance of the network [5M]
23 Determine total impedance of the circuit and also total current? [5M]
24 In the given figure Z
1
= 4 30 , Z
2
= 60 0 5 find I [5M]
Contd…6

17
25 In the below shown in figure R
1
=3 Ω R
2
=10 Ω and -jx c
= -j8 . Find I
1
, I
2 and I
[5M]
26.a) Define self and mutual inductances?
b) Obtain the expressions of self and mutual inductances. [5M]
27. Obtain the expression of self and mutual inductance? [5M]
28. Obtain the expression of mutual inductance an also coefficient of coupling? [5M]
29. Obtain the expression of inductance when two coils connected in series? [5M]
30 Two coupled coils have self inductance L
1
=10X 10 -3 H and L
2
= 20X10 -3 H . The coefficient of coupling (K) being 0.75 in the air, find voltage in the second coil and the flux of first coil provided the second coil has 500 turns and circuit is given by i
1
= 48in 3/4tA. [5M]
31. Find the total inductance of the three series connected coupled coils?
L
1
=1H L
2
= 2H L
3
= 5H M
12
= 0.5H, M
23
=1H, M
13
= 1H [5M]
Contd…7

18
32. Find the total inductance of the three series connected coupled coils
L
1
=1H L
2
=2H, L
3
=15H M
12
=0.6H M
23
=0.8H M
13
=0.6H [5M]
33 Find the total inductance of three series connected coupled coils as shown below.
L
1
=1H L
2
=2H L
3
= 5H M
12
= 0.5H M
23
=1H M
13
=1H [5M]
34. In the coupled circuit shown below find the input impedance as well as the net inductance? [5M]
Contd…8

19
35 Find the drop across R
2
[5M]
36. A flux of 0.5mwb is produced by a coil of 900 turns wound on a ring with a current of 3A in it calculate (i) inductance of coil (ii) e.mf induced in the coil, when a current of 5A is switched off, assuming the current to fall to zero in millisecond [5M]
37. A long solenoid of cross-section 2cm 2 has a primary winding with 25 turns per cm. At the middle is wound a secondary winding of 100 turns. The primary is suddenly disconnected from supply when carrying 2A, the current falling to zero on 1/1,000sec. Calculate the average emf induced in secondary? [5M]
38. Calculate the inductance of a toroidal coil of 100 turns wound uniformly on a non-magnetic core ring of mean diameter 140mm and the cross-sectional area is
750mm 2 [5M]
39. A coil with 250 turns carries a current of 2A and produces a flux of 0.3mwb. when this current is reduced to zero in 2 milliseconds, the voltage induced in a near by coil is 60volts. Calculate: i) self inductance of each coil ii) mutual inductance k=0.7. [5M]
40. A coil of 1,500 turns gives a rise to a magnetic flux of 2.5mwb, when carrying a certain current. If this current is completely reversed in 0.2 second, what is the average emf induced in the coil? [5M]
^*^*^