Q 1. A 68 Ω resistor is connected across the terminals of a 3 V battery. The power dissipation of the resistor is

(A) 132 mW
(B) 13.2 mW
(C) 22.6 mW
(D) 226 mW

Q 2. Energy is equal to power multiplied by voltage.

(A) True
(B) False

Q 3. A 120 Ω resistor must carry a maximum current of 25 mA. Its rating should be at least

(A) 4.8 W
(B) 150 mW
(C) 15 mW
(D) 480 mW

Q 4. When the pointer of an analog ohmmeter reads close to zero, the resistor being measured is

(A) Overheated
(B) Shorted
(C) Open
(D) Reversed

Q 5. The joule is a unit of energy.

(A) True
(B) False

Q 6. In 40 kW, there are

(A) 0.4 mW
(B) 40,000 W
(C) 400 W
(D) 5,000 W

Q 7. How much continuous current can be drawn from a 60 Ah battery for 14 h?

(A) 42.8 A
(B) 428 A
(C) 4.28 A
(D) 4.2 A

Q 8. The watt is the unit of power.

(A) True
(B) False

Q 9. A certain appliance uses 350 W. If it is allowed to run continuously for 24 days, how many kilowatt-hours of energy does it consume?

(A) 20.16 kWh
(B) 201.6 kWh
(C) 2.01 kWh
(D) 8.4 kWh

Q 10. For 12 V and 40 mA, the power is

(A) 480 mW
(B) 0.480 W
(C) 480,000 µW
(D) All of the above

Q 11. A half-watt is equal to how many milliwatts?

(A) 5,000 mW
(B) 5 mW
(C) 500 mW
(D) 50 mW

Q 12. A 75 Ω load uses 2 W of power. The output voltage of the power supply is approximately

(A) 120 V
(B) 1.2 V
(C) 12 V
(D) 6 V

Q 13. A resistor normally opens when it burns out.

(A) True
(B) False

Q 14. The power rating of a carbon-composition resistor that is to handle up to 1.2 W should be

(A) 2 W
(B) 1 W
(C) 5 W
(D) 0.5 W

Q 15. The capacity of a battery is measured in milli-amperes.

(A) True
(B) False

Q 16. A 33 Ω half-watt resistor and a 330 Ω half-watt resistor are connected across a 12 V source. Which one(s) will overheat?

(A) 33 Ω
(B) 330 Ω
(C) Both resistors
(D) Neither resistor

Q 17. A given power supply is capable of providing 6 A for 3.5 h. Its ampere-hour rating is

(A) 0.58 Ah
(B) 2.1 Ah
(C) 21 Ah
(D) 58 Ah

Q 18. A battery is one type of power supply that converts chemical energy into electrical energy.

(A) True
(B) False

Q 19. If it takes 400 ms to use 12,000 J of energy, the power is

(A) 30 kW
(B) 30 W
(C) 3 W
(D) 300 kW

Q 20. Three hundred joules of energy are consumed in 15 s. The power is

(A) 2,000 W
(B) 2 W
(C) 20 W
(D) 200 W

Q 21. A power supply produces a 0.6 W output with an input of 0.7 W. Its percentage of efficiency is

(A) 8.57 %
(B) 42.85 %
(C) 4.28 %
(D) 85.7 %

Q 22. A 15 V source is connected across a 12 Ω resistor. How much energy is used in three minutes?

(A) 938 Wh
(B) 0.938 Wh
(C) 56.25 Wh
(D) 5.6 Wh

Q 23. If you used 400 W of power for 30 h, you have used

(A) 1.3 kWh
(B) 13.3 kWh
(C) 1.2 kWh
(D) 12 kWh

Q 24. How many watt-hours represent 65 W used for 18 h?

(A) 11.7 Wh
(B) 1,170 Wh
(C) 11,700 Wh
(D) 117,000 Wh

Q 25. A 220 Ω resistor dissipates 3 W. The voltage is

(A) 73.3 V
(B) 2.5 V
(C) 25.7 V
(D) 257 V

Q 26. A 6 V battery is connected to a 300 Ω load. Under these conditions, it is rated at 40 Ah. How long can it supply current to the load?

(A) 1 h
(B) 200 h
(C) 2,000 h
(D) 10 h

Q 27. A 3.3 kΩ resistor dissipates 0.25 W. The current is

(A) 8.7 mA
(B) 87 mA
(C) 8.7 µA
(D) 8.7 A

Q 28. When the current through a 12 kΩ resistor is 8 mA, the power is

(A) 7.68 mW
(B) 768 mW
(C) 7.68 W
(D) 76.8 W

Q 29. Watt’s law states the relationships of power to energy.

(A) True
(B) False

Q 30. In 0.025 W, there are

(A) 25 kW
(B) 0.00025 mW
(C) 2,500 µW
(D) 25 mW

Q 31. Energy equals power multiplied by time.

(A) True
(B) False

Q 32. At the end of a 14 day period, your utility bill shows that you have used 18 kWh. What is your average daily power?

(A) 1.286 kWh
(B) 12.85 kWh
(C) 535 kWh
(D) 252 kWh

Q 33. The power rating of a resistor determines the minimum power that it can handle safely.

(A) True
(B) False

Q 34. If you used 600 W of power for 60 h, you have used

(A) 36 kWh
(B) 3.6 kWh
(C) 10 kWh
(D) 1 kWh