Electricity and Magnetism

Why are metals useful for making electrical wire?

• Metals are good conductors of electricity.
• Metals are good insulators of heat.
• Metals are resistant to corrosion.
• Metals are lightweight and flexible.

Which is NOT an insulator?

• Copper
• Wood
• Glass
• Rubber

The __________ wire only carries a current when there is a fault.

When the current through a fuse gets too high, the wire inside the fuse will...

• melt and break the circuit
• vibrate and create noise
• stay intact and allow current
• do nothing

What is the primary purpose of a circuit breaker in an electrical system?

• To provide a constant current flow.
• To protect against electrical fires

• To increase the voltage in the circuit.
• To enhance the efficiency of electrical devices.

The resistance of a light bulb is 30 ohms. If the current must double but the battery is remaining the same, the light bulb must be replaced by one with ____ ohms.

• 30 ohms (the light bulb resistance will not change)

• 15 ohms (new light bulb should have half the resistance)

• 60 ohms (new light bulb should have double the resistance)

What are the units of measure for current, voltage and resistance respectively?

• Current: A, Voltage: A, Resistance: V
• Current: C, Voltage: W, Resistance: R
• Current: mA, Voltage: kV, Resistance: MΩ
• Current: A, Voltage: V, Resistance: Ω

If a toaster produces 12 ohms of resistance in a 120-volt circuit, what is the amount of current in the circuit?

• 5 amps
• 10 amps
• 15 amps
• 20 amps

Which term matches the following definition?

Definition: The opposition to the flow of electrical current.

• Electrons

• Voltage
• Resistance
• Ohm's Law

A multimeter we used in the circuits measures...

• Voltage

• Current

• Resistance

• car speed