Electricity and Power Quiz

The current through a lightbulb connected across the terminals of a 125 V outlet is 0.5 A. At what rate does the bulb convert electric energy to light? (Assume 100 percent efficiency)

• 62.5 W
• 0.25 W
• 125 W
• 31.25 W

A car battery causes a current of 2 A through a lamp and produces 12 V across it. What is the power used by the lamp?

• 30 W
• 6 W
• 24 W
• 18 W

What is the current through a 75 W lightbulb that is connected to a 125 V outlet?

• 2.0 A
• 0.3 A
• 1.2 A
• 0.6 A

The current through a starter motor of a car is 210 A. If the battery maintains 12 V across the motor, how much electric energy is delivered to the starter in 10 s?

• 18000 J
• 2100 J
• 25200 J
• 24000 J

A flashlight bulb is rated 0.90 W. If the light bulb drops 3 V, how much current goes through it?

• 0.45 A
• 0.60 A
• 0.75 A
• 0.30 A

An automobile panel lamp with a resistance of 33 is placed across a 12 V battery. What is the current through the circuit?

• 0.5 A
• 0.666 A
• 0.25 A
• 0.3636 A

A motor with an operating resistance of 32 is connected to a voltage source. The current in the circuit is 3.8 A. What is the voltage of the source?

• 98.4 V
• 110.6 V
• 121.6 V
• 135.2 V

A sensor uses 20,000 A of current when it is operated by a 3 V battery. What is the resistance of the sensor circuit?

• 5000 ohms
• 10000 ohms
• 20000 ohms
• 15000 ohms

A lamp draws a current of 0.5 A when it is connected to a 120 V source. What is the resistance of the lamp?

• 320 ohms
• 60 ohms
• 240 ohms
• 180 ohms

A 75 W lamp is connected to 125 V, what is the resistance of the lamp?

• 300 ohms
• 210 ohms

• 100 ohms
• 150 ohms