⚡ 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 induced voltage across a stationary conductor in a stationary magnetic field isAnswer: zero An electromagnetic field exists only when there isAnswer: current When a solenoid is activated, the force that moves the plunger isAnswer: an electromagnetic field What is the magnetomotive force (mmf) of a wire with 8 turns carrying three amperes of current?Answer: 24 At If a loop in a basic dc generator suddenly begins rotating at a faster speed, the induced voltageAnswer: increases If the rms voltage drop across a 15 k resistor is 16 V, the peak current through the resistor isAnswer: 1.5 mA The conductive loop on the rotor of a simple two-pole, single-phase generator rotates at a rate of 400 rps. The frequency of the induced output voltage isAnswer: 400 Hz How many degrees are there in /3 rad?Answer: 60° To produce an 800 Hz sine wave, a four-pole generator must be operated atAnswer: 400 rps One sine wave has a positive-going zero crossing at 15° and another sine wave has a positive-going zero crossing at 55°. The phase angle between the two waveforms isAnswer: 40° If the rms current through a 4.7 k resistor is 4 mA, the peak voltage drop across the resistor isAnswer: 26.6 V A pulse waveform has a high time of 8 ms and a pulse width of 32 ms. The duty cycle isAnswer: 25% A 20 kHz pulse waveform consists of pulses that are 15 μ s wide. The duty cycleAnswer: is 30% If the peak of a sine wave is 13 V, the peak-to-peak value isAnswer: 26 V A sinusoidal current has an rms value of 14 mA. The peak-to-peak value isAnswer: 39.6 mA A signal with a 400 μ s period has a frequency ofAnswer: 2,500 Hz A sine wave of 15 kHz is changing at a faster rate than a sine wave with a frequency ofAnswer: 12 kHz The average value of a 12 V peak sine wave over one complete cycle isAnswer: 0 V When a sine wave has a frequency of 100 Hz in 12 s it goes throughAnswer: 1,200 cycles A sawtooth wave has a period of 10 ms. Its frequency isAnswer: 100 Hz Two series resistors are connected to an ac source. If there are 7.5 V rms across one resistor and 4.2 V rms across the other, the peak source voltage isAnswer: 16.54 V If a sine wave goes through 10 cycles in 20 μs, the period isAnswer: 2 μs A square wave has a period of 60 μ s. The first odd harmonic isAnswer: 50 kHz Sine wave A has a positive-going zero crossing at 45°. Sine wave B has a positive-going zero crossing at 60°. Which of the following statements is true?Answer: Wave A leads wave B by 15°. A phasor representsAnswer: the magnitude and a quantity direction A sine wave with a period of 4 ms is changing at a faster rate than a sine wave with a period ofAnswer: 0.0045 s A waveform has a baseline of 3 V, a duty cycle of 20%, and an amplitude of 8 V. The average voltage value isAnswer: 4 V A sine wave with an rms value of 12 V is riding on a dc level of 18 V. The maximum value of the resulting waveform isAnswer: 35 V If the rms current through a 6.8 kΩ resistor is 8 mA, the rms voltage drop across the resistor isAnswer: 54.4 V The average half-cycle value of a sine wave with a 40 V peak isAnswer: 25.48 V