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Network Theory Set-4
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1. If there are M meshes, B branches and N nodes including reference node, the number of mesh currents is given as M=?
B + (N+1)
B + (N-1)
B-(N+1)
B-(N-1)
2. If there are N nodes in a circuit, then the number of nodal equations that can be formed are?
N+1
N
N-1
N-2
3. Superposition theorem states that the response in any element is the ____________ of the responses that can be expected to flow if each source acts independently of other sources.
algebraic sum
vector sum
multiplication
subtraction
4. Superposition theorem is valid for only linear systems.
true
false
5. Thevenin’s voltage is equal to the _____________ voltage across the _______________ terminals.
short circuit, input
short circuit, output
open circuit, output
open circuit, input
6. Norton’s current is equal to the current passing through the ___________ circuited ___________ terminals.
short, input
short, output
open, output
open, input
7. The condition for maximum voltage to be transferred to the load is?
Source resistance greater than load resistance
Source resistance less than load resistance
Source resistance equal to load resistance
Source resistance greater than or equal to load resistance
8. The condition for maximum current to be transferred to the load is?
Source resistance greater than or equal to load resistance
Source resistance equal to load resistance
Source resistance less than load resistance
Source resistance greater than load resistance
9. The condition for maximum power to be transferred to the load is?
Source resistance equal to load resistance
Source resistance greater than load resistance
Source resistance greater than or equal to load resistance
Source resistance less than load resistance
10. At resonant frequency, the voltage across capacitor is _______ the voltage across inductor.
greater than
less than
greater than or equal to
equal to
11. The voltage across the LC combination in a series RLC circuit is?
0
1
2
3
12. The expression of resonant frequency in a series resonant circuit is?
1/(2π√C)
1/( 2π√L)
2π√LC
1/(2π√LC)
13. Determine the resonant frequency for the specifications: R = 10Ω, L = 0.1H, C = 10µF.
157
158
159
160
14. The expression for bandwidth is?
R/πL
R/2πL
R/4πL
R/8πL
15. If a series circuit contains resistor and capacitor, the expression for quality factor is?
C
ωRC
ωC
1/ωRC
16. The quality factor of the coil for a series circuit having R = 10Ω, L = 0.1H, C = 10µF.
1
5
10
15
17. The expression of resonant frequency for parallel resonant circuit is?
1/(2π√LC)
1/(π√LC)
1/(2√LC)
1/√LC
18. If the value of Q of the circuit is high, then its effect on bandwidth is?
large bandwidth
small bandwidth
no effect on bandwidth
first increases and then decreases
19. If in a circuit, if Q value is decreased then it will cause?
small bandwidth
no effect on bandwidth
first increases and then decreases
large bandwidth
20. The expression of ωr in a parallel resonant circuit is?
1/(2√LC)
1/√LC
1/(π√LC)
1/(2π√LC)
21. The expression of bandwidth for the parallel resonant circuit is?
1/RC
RC
1/R
1/C
22. The quality factor is the product of 2π and the ratio of ______ to _________
maximum energy stored, energy dissipated per cycle
energy dissipated per cycle, maximum energy stored
maximum energy stored per cycle, energy dissipated
energy dissipated, maximum energy stored per cycle
23. A circuit tuned to a frequency of 1.5 MHz and having an effective capacitance of 150 pF. In this circuit, the current falls to 70.7 % of its resonant value. The frequency deviates from the resonant frequency by 5 kHz. Effective resistance of the circuit is?
2 Ω
3 Ω
5.5 Ω
4.7 Ω
24. A 50 μF capacitor, when connected in series with a coil having a resistance of 40Ω, resonates at 1000 Hz. The inductance of the coil for the resonant circuit is ____________
2.5 mH
1.2 mH
0.5 mH
0.1 mH
25. A coil (which can be modelled as a series RL circuit) has been designed for a high Quality Factor (Q) performance. The voltage is rated at and a specified frequency. If the frequency of operation is increased 10 times and the coil is operated at the same rated voltage. The new value of Q factor and the active power P will be?
P is doubled and Q is halved
P is halved and Q is doubled
P remains constant and Q is doubled
P decreases 100 times and Q is increased 10 times
26. A 440 V, 50 HZ AC source supplies a series LCR circuit with a capacitor and a coil. If the coil has 100 mΩ resistance and 15 mH inductance, then at a resonance frequency of 50 Hz, the half power frequencies of the circuit are?
50.53 Hz, 49.57 Hz
52.12 HZ, 49.8 Hz
55.02 Hz, 48.95 Hz
50 HZ, 49 Hz
27. At what frequency will the current lead the voltage by 30° in a series circuit with R = 10Ω and C = 25 μF?
11.4 kHz
4.5 kHz
1.1 kHz
24.74 kHz
28. A 440 V, 50 HZ AC source supplies a series LCR circuit with a capacitor and a coil. If the coil has 100 mΩ resistance and 15 mH inductance, then at a resonance frequency of 50 Hz, what is the value of the capacitor?
676 μF
575 μF
591 μF
610 μF
29. A 440 V, 50 HZ AC source supplies a series LCR circuit with a capacitor and a coil. If the coil has 100 mΩ resistance and 15 mH inductance, then at a resonance frequency of 50 Hz, the Q factor of the circuit is?
82.63
47.115
27.38
92.38
30. A series RLC circuit has a resonance frequency of 1 kHz and a quality factor Q = 50. If R and L are doubled and C is kept same, the new Q of the circuit is?
25.52
35.35
45.45
20.02
31. In a series RLC circuit for lower frequency and for higher frequency, power factors are respectively ______________
Leading, Lagging
Lagging, Leading
Independent of Frequency
Same in both cases
32. For a parallel RLC circuit, the incorrect statement among the following is _____________
The bandwidth of the circuit decreases if R is increased
The bandwidth of the circuit remains same if L is increased
At resonance, input impedance is a real quantity
At resonance, the magnitude of input impedance attains its minimum value
33. For a series RLC circuit, excited by voltage V = 20 sinωt. The values of R = 2 Ω, L = 1mH and C = 0.4 µF. The resonant frequency of the circuit is ______________
20 krad/s
30 krad/s
40 krad/s
50 krad/s
34. For a series RLC circuit, excited by voltage V = 20 sinωt. The values of R = 2 Ω, L = 1mH and C = 0.4 µF. The quality factor and bandwidth of the circuit is ______________
25, 2
30, 5
40, 10
50, 2
35. An ideal transformer is rated as 2400/120 V, 9.6 kVA and has 50 turns on the secondary side. The turns ratio is ____________
0.04
0.05
0.06
0.07
36. A 50 μF capacitor, when connected in series with a coil having a resistance of 40Ω, resonates at 1000 Hz. The circuit is in resonating condition. The voltage across the capacitor is __________
8.04 V
7.96 V
5.68 V
1.25 V
37. An ideal transformer is rated as 2400/120 V, 9.6 kVA and has 50 turns on the secondary side. The number of turns on the primary side is ____________
1000
2000
3000
4000
38. A 50 μF capacitor, when connected in series with a coil having resistance of 40Ω, resonates at 1000 Hz. The circuit current if the applied voltage is 100 V for the resonant circuit is ___________
2.5 A
3.5 A
4.5 A
0.5 A
39. A 50 μF capacitor, when connected in series with a coil having resistance of 40Ω, resonates at 1000 Hz. The circuit is in resonating condition. The voltage across the coil is __________
100.31 V
200.31 V
300.31 V
400.31 V
40. A series RLC circuit has a resonance frequency of 1 kHz and a quality factor Q = 100. If each of R, L and C is doubled from its original value, the new Q of the circuit is _____________
25
50
100
200
41. The current through an electrical conductor is 1A when the temperature of the conductor 0°C and 0.7 A when the temperature is 100°C. The current when the temperature of the conductor is 1200°C is ___________
0.08 A
0.16 A
0.32 A
0.64 A
42. An air capacitor of capacitance 0.005 μF is connected to a direct voltage of 500 V. It is disconnected and then immersed in oil with a relative permittivity of 2.5. The energy after immersion is?
275 μJ
250 μJ
225 μJ
625 μJ
43. A capacitor of capacitance 50 μF is connected in parallel to another capacitor of capacitance 100 μF. They are connected across a time-varying voltage source. At a particular time, the current supplied by the source is 5 A. The magnitude of instantaneous current through the capacitor of capacitance 50 μF is?
1.57 A
1.87 A
1.67 A
2.83 A
44. A capacitor of capacitance 50 μF is connected in parallel to another capacitor of capacitance 100 μF. They are connected across a time-varying voltage source. At a particular time, the current supplied by the source is 5 A. The magnitude of instantaneous current through the capacitor of capacitance 100 μF is?
2.33 A
3.33 A
1.33 A
4.33 A
45. The voltage drop across a standard resistor of 0.2 Ω is balanced at 83 cm. The magnitude of the current, if the standard cell emf of 1.53 V is balanced at 42 m is ___________
13.04 A
10 A
14.95 A
12.56 A
46. The simultaneous applications of signals x (t) and y (t) to the horizontal and vertical plates respectively, of an oscilloscope, produce a vertical figure of 8 displays. If P and Q are constants and x(t) = P sin (4t + 30), then y(t) is equal to _________
Q sin (4t – 30)
Q sin (2t + 15)
Q sin (8t + 60)
Q sin (4t + 30)
47. A resistor of 10 kΩ with a tolerance of 5% is connected in parallel with 5 kΩ resistors of 10% tolerance. The tolerance limit is __________
9%
12.4%
8.33%
7.87%
48. A 200/1 Current Transformer (CT) is wound with 400 turns on the secondary on a toroidal core. When it carries a current of 180 A on the primary, the ratio is found to be -0.5%. If the number of secondary turns is reduced by 1, the new ratio error (in %) will be?
0.0
-0.5
-1.0
-2.0
49. In the Two wattmeter method of measuring power in a balanced three-phase circuit, one wattmeter shows zero and the other positive maximum. The load power factor is ___________
0
0.5
0.866
1.0
50. The meter constant of a single-phase, 230 V induction watt-meter is 600 rev/kW-h. The speed of the meter disc for a current of 15 A at 0.8 power factor lagging will be?
30.3 rpm
25.02 rpm
27.6 rpm
33.1 rpm
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