⚡ Electrical Engineering Solved MCQs with Answers

Practice 757 approved ⚡ Electrical Engineering questions with verified answers from the 🛠️ Engineering Essentials subject for Pakistan exams.

757 solved MCQs

The complex number 40< 55° is equivalent toAnswer: 22.94 + j32.76 A 120 Ω resistor is in parallel with a capacitor with a capacitive reactance of 40 Ω. Both components are across a 12 V ac source. What is the magnitude of the total impedance?Answer: 37.9 Ω A 47 Ω resistor and a capacitor with 150 Ω of capacitive reactance are in series across an ac source. The impedance, expressed in rectangular form, isAnswer: Z = 47 Ω – j150 Ω A 2 kΩ resistor and a 0.002 μF capacitor are in series across an ac source. Current in the circuit is 6.50 mA. The true power isAnswer: 84.5 mW A capacitor with 150 Ω of capacitive reactance is across an ac source. The impedance, expressed in polar form, isAnswer: Z = 150 <–90°Ω When the frequency of the voltage applied to a series RC circuit is decreased, the impedanceAnswer: Increases A 1.5 kΩ resistor and a coil with a 2.2 kΩ inductive reactance are in series across an 18 V ac source. The power factor isAnswer: 0.564 The voltages in Problem 5 are measured at a certain frequency. To make the resistor voltage less than the inductor voltage, the frequency isAnswer: increased In a series RL circuit, 12 V rms is measured across the resistor, and 14 V rms is measured across the inductor. The peak value of the source voltage isAnswer: 26.0 V To increase the current in a series RL circuit, the frequencyAnswer: should be decreased A 470 Ω resistor and a coil with 125 Ω inductive reactance are in parallel. Both components are across a 15 V ac voltage source. Current through the inductor isAnswer: 120 mA A 1.2 kΩ resistor is in series with a 15 mH coil across a 10 kHz ac source. The magnitude of the total impedance isAnswer: 1,526 Ω When the frequency is decreased, the impedance of a parallel RL circuitAnswer: decreases A 470 resistor and a 200 mH coil are in parallel. Both components are across a 1.5 kHz ac source. The total admittance of the circuit, in polar form, isAnswer: 12.18 <–76° mS Referring to Problem 23, the reactive power isAnswer: 100 mVAR A 12 kΩ resistor is in series with a 90 mH coil across an 8 kHz ac source. Current flow in the circuit, expressed in polar form, is I = 0.3<0° mA. The source voltage, expressed in polar form, isAnswer: 3.84<20.6° V A 140 Ω resistor is in parallel with an inductor having 60 Ω inductive reactance. Both components are across a 12 V ac source. The magnitude of the total impedance isAnswer: 55.15 Ω When the frequency of the voltage applied to a series RL circuit is decreased, the impedanceAnswer: decreases In a parallel RL circuit, there are 3 A rms in the resistive branch and 3 A rms in the inductive branch. The total rms current isAnswer: 4.24 A A 47 resistor is in series with an inductive reactance of 120 across an ac source. The impedance, expressed in polar form, isAnswer: 129<68.6° When the resistor voltage in a series RL circuit becomes less than the inductor voltage, the phase angleAnswer: increases Which of the following power factors results in less energy loss in an RL circuit?Answer: 0.2 A 3.3 kΩ resistor and a 120 mH coil are in parallel. Both components are across a 2 kHz, 12 V ac source. The total current in the circuit isAnswer: 8.74 mA When the frequency of the voltage applied to a series RL circuit is increased, the phase angleAnswer: increases If a load is purely inductive and the reactive power is 12 VAR, the apparent power isAnswer: 12 VA If the frequency is halved and the resistance is doubled, the impedance of a series RL circuitAnswer: cannot be determined without values A 10 Ω resistor, a 90 mH coil, and a 0.015 F capacitor are in series across an ac source. The impedance magnitude at 1,200 Hz below fr isAnswer: 1,616Ω In a series RLC circuit that is operating above the resonant frequency, the currentAnswer: lags the applied voltage A 15 Ω resistor, a 220 μH coil, and a 60 pF capacitor are in series across an ac source. What is the bandwidth of the circuit?Answer: 10,866 Hz A resistor of 3 kΩ, a 0.05 μF capacitor, and a 120 mH coil are in series across a 5 kHz, 20 V ac source. What is the impedance, expressed in polar form?Answer: 4,337 Ω