# Basic Electrical Power and Energy MCQs

Basic Electrical Power and Energy MCQs

## The kilowatt-hour is the unit of

The kilowatt-hour is the unit of

1. Charge
2. Current
3. Energy
4. Power

## Heater element in an electric iron is made of

Heater element in an electric iron is made of:

1. Iron
2. Nichrome
3. Constantan
4. Tungsten

## Two bulbs, 80 W, 250 V and 150 W, 250 V are connected in parallel across a 500 V line, which of following is correct

Two bulbs, 80 W, 250 V and 150 W, 250 V are connected in parallel across a 500 V line, which of following is correct:

1. 80 W bulb will be fused
2. 150 W bulb will be fused
3. Both bulbs will be fused
4. No bulb will be fused

Correct answer: 3. Both bulbs will be fused

## Heat produced in a conductor having 3.5 ohms with 5 A flowing in it is

Heat produced in a conductor having 3.5 ohms with 5 A flowing in it is:

1. 10 cal/sec
2. 13 cal/sec
3. 21 cal/sec
4. 35 cal/sec

Explanation: Power (Watts) = I^2*R = (5)^2 * 3.5 = 25 * 3.5 = 87.5 watts

1 watt = 0.24 calories per second

87.5 watts = 87.5 * 0.24 = 21 cal/sec

## The power rating of a motor drawing a current of 20 A at 230 V is

The power rating of a motor drawing a current of 20 A at 230 V is

1. 1000 W
2. 2000 W
3. 4600 W
4. 9400 W