Electrical Engineering · Question Bank

1P AC Circuits

161 questions · page 2 of 9. Answer in your head first, then check the solution.

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TypeAll 161Problem solving 77Objective 84
DifficultyAll 161Easy 136Medium 22Hard 3
#21📜 EE Pre-Board August 2013📘 PowerhouseEasy
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.
A200 v
B100 V
C75 v
D50 v
#22📜 EE Pre-Board August 2013📘 PowerhouseEasy
A resistance of 40 ohms and inductance of 79.6 mH are connected in parallel across a 240 v, 60 HZ ac supply. Find the total current in amperes.
A11
B12
C10
D14
#23📜 EE Pre-Board March 2014📘 PowerhouseEasy
Form factor is defined as
Arms value/peak value
Bmaximum value/rms value
Crms value/average value
Deffective value/rms value
#24📜 EE Pre-Board March 2014📘 PowerhouseEasy
The value of form factor for a pure sine wave is
A1.414
B0.707
C0.637
D1.11
#25📜 EE Pre-Board March 2014📘 PowerhouseEasy
The rms value of a sinusoidal wave is equal to ______ of maximum value.
A0.637
B0.707
C0.506
D1.414
#26📜 EE Pre-Board March 2014📘 PowerhouseMedium
A circuit has a resonant frequency of 4,000 rad/sec and bandwidth of 100 rad/sec. If the resistance is 5 ohms, find the values of L and C.
A50 mH, 1.25 μF
B1.25 mH, 50 μF
C5 mH, 12.5 μF
D12.5 mH, 5 μF
#27📜 EE Pre-Board March 2014📘 PowerhouseEasy
A 99 MHz radio station has a 150 μH inductor. What is the capacitance?
A0.0172 pF
B17.2 pF
C1.72 μF
D17.2 μF
#28📜 EE Pre-Board March 2014📘 PowerhouseEasy
Express the current phasor \(25\angle -30^\circ\) as an instantaneous current.
A\(17.68\sin(\omega t - 30^\circ)\)
B\(35.35\sin(\omega t + 30^\circ)\)
C\(35.35\sin(\omega t - 30^\circ)\)
D\(25\sin(\omega t - 30^\circ)\)
#29📜 EE Pre-Board March 2014📘 PowerhouseEasy
A series RLC circuit has R = 100 ohms, L = 100 μH and C = 100 pF. What is the frequency in MHz at unity power factor?
A1.59
B1.36
C15.9
D13.6
#30📜 EE Pre-Board March 2014📘 PowerhouseMedium
An impedance draws a current of \(i = 10\cos(\omega t - 30^\circ)\) A from a supply with voltage \(e = 220\sin\omega t\) V. What is the impedance in ohms?
A11 + j19.05
B11 − j19.05
C19.05 + j11
D19.05 − j11
#31📜 EE Pre-Board March 2014📘 PowerhouseMedium
An impedance of 4 − j3 ohms is connected in parallel with an ideal inductor L across a 110 V, 60 Hz supply. Determine L if the total voltage supplied will be in phase with the total current drawn.
A16.6 mH
B19.2 mH
C22.1 mH
D26.8 mH
#32📜 EE Pre-Board March 2014📘 PowerhouseHard
A series RL circuit in which R = 5 Ω and L = 20 mH has an applied voltage \(e = 100 + 50\sin\omega t + 25\sin 3\omega t\), with ω = 500 rad/s. Determine the power dissipated in the resistor of the circuit.
A2,510 W
B2,234 W
C2,302 W
D2,052 W
#33📜 EE Pre-Board March 2014📘 PowerhouseEasy
An inductor has a value of 44 mH at 60 Hz. What is the inductive susceptance, stated as an imaginary number?
A−j0.06
Bj0.06
C−j17
Dj17
#34📜 EE Pre-Board August 2014📘 PowerhouseEasy
The current following in L and C at parallel resonance are
Azero
Bequal
Cinfinite
Ddifferent
#35📜 EE Pre-Board August 2014📘 PowerhouseEasy
At resonance, the impedance of a series RLC circuit is
Amaximum
Bminimum
Cinfinity
Dzero
#36📜 EE Pre-Board August 2014📘 PowerhouseEasy
At resonance, the current in a series RLC circuit is
Amaximum
Bminimum
Cinfinity
Dzero
#37📜 EE Pre-Board August 2014📘 PowerhouseEasy
In parallel RC circuit as the value of frequency increases the power factor _____.
ARemains the same
BBecomes unity
Cdecreases
Dincreases
#38📜 EE Pre-Board August 2014📘 PowerhouseMedium
A 2-element series circuit consumes 700 W and has a p.f. of 0.707 leading. If the applied voltage is \(v = 141\sin(314t + 30^\circ)\), find the circuit constants.
AR = 7.14 Ω, C = 44.6 μF
BR = 7.14 Ω, C = 446 μF
CR = 71.4 Ω, C = 44.6 μF
DR = 71.4 Ω, C = 446 μF
#39📜 EE Pre-Board August 2014📘 PowerhouseEasy
The rms value of sinusoidal ac current is equal to its value at an angle of ______ degrees.
A45
B30
C90
D60
#40📜 EE Pre-Board August 2014📘 PowerhouseEasy
The current in a circuit is given by \(i = 50\sin\omega t\). If the frequency is 25 Hz, how long will it take for the current to rise to 25 A?
A0.02 sec
B\(3.33 \times 10^{-3}\) sec
C0.05 sec
D0.033 sec

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