MCQs

An isolation transformer has primary to secondary turns ratio of: 1:1 1:2 2:1 Any of above Correct answer: 1. 1:1

The capacitance of a parallel plate capacitor depends on: Plate area Plate separation Dielectric All of above Correct answer: All of above Formula Hint: C = ε * (A/d)

Two bulbs of 100 W 230 V and 150 W, 230 V are connected in parallel to a 440 V supply line. What happens next 100 W bulb will be fused 150 W bulb will be fused Both bulbs will be fused None of them will be fused Correct answer: 3. Both bulbs will be … Read more

The value of output resistance of a voltage source is 5 ohms. Its internal resistance is: 1 ohm 2.5 ohms 5 ohms Can’t predict Correct answer: 3. 5 ohms The output resistance a voltage sources means its internal resistance. So the internal resistance of source is 5 ohms.

A voltmeter is connected to the plates of a charged capacitor. If plates of the capacitor are separated further, the reading of voltmeter will: Increase Decrease Remain constant Exponentially decrease Correct answer: 1. Increase

In Electrical Machines the hysteresis effect results in: Power loss Reduction of efficiency Raising temperature of machine All of above Correct answer: 4. All of above

The capacitor start, capacitor run induction motor acts as a true 2-phase motor at which of the following condition: No load All load Full load Starting Correct answer: 3. Full load

A DC series motor will over speed for which of the following condition: When field is opened When load is increased When armature circuit opened When load is removed Correct answer: 4. When load is removed

The flux in core of single phase transformer is: Purely rotating one Purely alternating one Partly alternating and partly rotating None of above Correct answer: 2. Purely alternating one

A 50 W bulb will provide heat and light energy of approximately: 200 J/s 100 J/s 50 J/s 25 J/s Correct answer: 3. 50 J/s A 50 W bulb will generate heat and light energy of approximately 50 J/s Good to know: 1 watt = 1 J/s