WorksheetsAC Fundamentals - III
Total questions: 22
Worksheet time: 36mins
If the load impedance is 20 − j20, the power factor is _______
0.5
0
1
0.7071
If there is complex impedance in a circuit, part of energy is ____________ by reactive part and part of its energy is ____________ by the resistance.
alternately stored and returned, alternately stored and returned
alternately stored and returned, dissipated
dissipated, alternately stored and returned
dissipated, dissipated
If power factor = 1, then the current to the load is ______ with the voltage across it.
out of phase
in phase
90⁰ out of phase
45⁰ out of phase
A sinusoidal voltage v = 50sinωt is applied to a series RL circuit. The current in the circuit is given by I = 25sin (ωt-53⁰). Determine the apparent power (VA).
620
625
630
635
At resonant frequency, the voltage across capacitor is _______ the voltage across inductor.
greater than
less than
greater than or equal to
equal to
In series RLC circuit, the voltage across capacitor and inductor are ______ with each other.
in phase
180⁰ out of phase
90⁰ out of phase
45⁰ out of phase
For the circuit shown in figure determine the capacitive reactance at resonance.
15
20
25
30
Determine the resonant frequency (kHz) for the circuit shown below.
2.25 kHz
22.5 kHz
225 kHz
2250 kHz
Find the resonant frequency in the ideal parallel LC circuit shown in the figure
7.118 Hz
71.18 Hz
711.8 Hz
7118 Hz
For the two magnetically coupled coils of Fig, the polarity of the mutual voltage is:
Positive
Negative
The ideal transformer has N2∕N1 = 10. The ratio V2∕V1 is:
10
0.1
-0.1
-10
A 230V, 50Hz voltage is applied to a coil having L = 5H and R = 2 Ohm in series with capacitance C. When the voltage across the coil is 400V, find the current in the circuit?
0.1465 A
0.1578 A
0.2547 A
0.4583 A
A 230V, 50Hz voltage is applied to a coil having L = 5H and R = 2 Ohm in series with capacitance C. When the voltage across the coil is 400V, find the value of C?
10.54 µF
8.51 µF
1.8 µF
4.78 µF
A series RLC circuit is connected across a 240V, 50 Hz supply. When the voltage across capacitor is 250V, a maximum current of 0.5A flows in the circuit. Find the resistance.
480 Ohms
500 Ohms
100 Ohms
1000 Ohms
A series RLC circuit is connected across a 240V, 50 Hz supply. When the voltage across capacitor is 250V, a maximum current of 0.5A flows in the circuit. Find the capacitance.
2.55 H
1.95 H
1.59 H
0.45 H
A series circuit consists of R = 20 Ω, L = 20 mH, and AC supply 60 V with f = 100 Hz. The current in R is
2.54 A
1.27 A
5.08 A
10.16 A
A series circuit consists of R = 20 Ω, L = 20 mH, and AC supply 60 V with f = 100 Hz. The phase angle of current in respect of supply voltage will be
40.4o
32.1o
28.8o
20.2o
A series circuit consists of R = 20 Ω, L = 20 mH, and AC supply 60 V with f = 100 Hz. The voltage drop across R is
30.6 V
50.8 V
40.8 V
24.4 V
For the resonance circuit ω0 = 105, Q = 50, R = 400 Ω the value of C is
250 pF
500 pF
1000 pF
125 pF
A series circuit consists of R = 20 Ω, L = 20 mH, and AC supply 60 V with f = 100 Hz. The voltage drop across L is
39.1 V
31.9 V
45.5 V
50.5 V
The active and reactive power in an AC circuit are 10W and 20VAR respectively. What is the power factor?
0.866
0.5
0.577
1
Unit of apparent power is _____
watts
VA
VAr
kWhr
