Basic Electrical Power and Energy MCQs
Contents
- 1 The kilowatt-hour is the unit of
- 2 Heater element in an electric iron is made of
- 3 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
- 4 Heat produced in a conductor having 3.5 ohms with 5 A flowing in it is
- 5 The power rating of a motor drawing a current of 20 A at 230 V is
The kilowatt-hour is the unit of
The kilowatt-hour is the unit of
- Charge
- Current
- Energy
- Power
Correct answer: 3. Energy
Heater element in an electric iron is made of
Heater element in an electric iron is made of:
- Iron
- Nichrome
- Constantan
- Tungsten
Correct answer: 2. Nichrome
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:
- 80 W bulb will be fused
- 150 W bulb will be fused
- Both bulbs will be fused
- 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:
- 10 cal/sec
- 13 cal/sec
- 21 cal/sec
- 35 cal/sec
Correct answer: 3. 21 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
- 1000 W
- 2000 W
- 4600 W
- 9400 W
Correct answer: 3. 4600 W