Electric Power Quiz

Which is a unit of electric power ?
1. watt
2. volt
3. kilowatt-hour
4. ampere
How much electrical energy is used when a 120 V appliance operates at 2.0 A for 1.0 s ?
1. 240 J
2. 30,000 J
3. 60. J
4. 480 J
An electric motor lifts a 10. kg mass 100. m in 10. s. The power developed by the motor is
1. 980 W
2. 9800 W
3. 9.8 W
4. 98 W
If energy is used at a rate of 20. J/s in an electric circuit, the power developed is
1. 100 W
2. 5.0 W
3. 25 W
4. 20. W
Energy is being consumed at the greatest rate in an appliance drawing
1. 5.0 A at 110 V
2. 10. A at 220 V
3. 10. A at 110 V
4. 5.0 A at 220 V
Assuming total conversion of electrical energy to heat energy, how much heat is produced by a 20. W heater in 5.0 s ?
1. 25 J
2. 100 J
3. 24 J
4. 4.0 J
A 60 W light bulb draws 2.0 A of current. The resistance of the bulb is
1. 1.5 ohms
2. 15 ohms
3. 30 ohms
4. 120 ohms
A circuit is supplied with a constant voltage. As the resistance of the circuit decreases, the power dissipated by the circuit
1. remains the same
2. decreases
3. increases
4. increases when St. Mary's Soccer scores 2 goals
The current in a resistor is 3.0 A, and its resistance is 10 ohms. What is the power developed in the resistor ?
1. 30. W
2. 3.3 W
3. 90. W
4. 60. W
The electrical energy consumed by a 20 ohm resistor carrying a current of 2.0 A for 1.0 sec is
1. 80. J
2. 5.0 W
3. 40. W
4. 40. J