⚡ 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

An RC differentiator acts as aAnswer: high-pass filter In an RL differentiator, when the input pulse goes from its low level to its high level,Answer: the inductor prevents a sudden change in current In an RC differentiator, responding to repetitive pulses, the average value of the outputAnswer: is zero The output of an RC integrator is taken across theAnswer: capacitor When a 24 V input pulse with a width equal to five time constants is applied to an RC integrator, the capacitor charges toAnswer: 24 V If the RC time constant of an integrator is increased, as the time constant is increasedAnswer: the capacitor charges less during a pulse and discharges less between pulses If a periodic pulse waveform has a pulse width and the time between pulses each equal to or greater than five time constants, the capacitor willAnswer: fully charge and fully discharge during each period of the input waveform What is the highest frequency contained in a pulse that has a rise and fall time equal to 10 microseconds (10 μ s)?Answer: 35 kHz In electronic systems, repetitive-pulse waveforms are encounteredAnswer: more often than single pulses In an RC differentiator, the capacitorAnswer: charges exponentially at a rate depending on the RC time constant In a three-phase system, the voltages are separated byAnswer: 120° In a three-phase system, when the loads are perfectly balanced, the neutral current isAnswer: zero In a Δ-connected source driving a Δ-connected load, theAnswer: load voltage and line voltage are two-thirds the source voltage for a given phase In a certain three-wire Y-connected generator, the phase voltages are 2 kV. The magnitudes of the line voltages areAnswer: 3,464 V In a Δ-connected source feeding a Y-connected load,Answer: each phase voltage equals the difference of the corresponding load voltages In a Y-Y source/load configuration, theAnswer: phase current, the line current, and the load current are all equal in each phase In a Y-connected circuit, the magnitude of each line current isAnswer: equal to the corresponding phase current A constant load power means a uniform conversion ofAnswer: electrical to mechanical energy A three-phase generator is connected to three 90 Ω load resistors. Each coil generates 120 V ac. A common neutral line exists. How much current flows through the common neutral line?Answer: 0 A Compare the total copper cross sections in terms of current-carrying capacity for a single-phase and a three-phase 120 V system with effective load resistance of 15 Ω.Answer: single-phase 16 A; three-phase 8 A If in a Y-connected ac generator, each phase voltage has a magnitude of 90 VRMS, what is the magnitude of each line voltage?Answer: 156 V Polyphase generators produce simultaneous multiple sinusoidal voltages that are separated byAnswer: certain constant phase angles In a balanced three-phase load, each phase hasAnswer: an equal amount of power In a certain Y-Y system, the source phase currents each have a magnitude of 9 A. The magnitude of each load current for a balanced load condition isAnswer: 9 A In a Y-connected circuit, between each line voltage and the nearest phase voltage, there is a phase angle ofAnswer: 30° The most common type of ac motor is theAnswer: three-phase induction motor In a Y-connected source feeding a Δ-connected load,Answer: each phase of the load has the full line voltage across it In a Δ-connected generator, all of the phase voltages areAnswer: equal in magnitude 1 kilowatt hour (kWh) is the energy equal to _____?Answer: 3,600,000 J Two resistance of 2Ω each are connected in parallel to each other resultant resistance will be _____?Answer: 1Ω