Unit 3 MidPoint Quiz

Which of the following best describes electric charge?

• a force that causes objects to heat up

• a high-voltage material that can cause damage to objects

• a fundamental property that causes electric and magnetic interactions

• a particle that moves freely through matter and causes static electricity to build up on objects

When Bethany walks across a carpet, her socks pick up many negative electric charges. Later in the day, these negative charges are no longer present on her socks. What most likely happened to the negative charges?

• The charges disappeared.

• The charges transferred to another object.

• The charges switched from negative to positive.

• The charges broke apart into smaller positive and negative particles.

An engineer is building an electronic device.She wants to use a material that will give her the most control over the amount of electric charge that flows through a circuit. Which material should she use?

• conductor

• insulator

• semiconductor

• metal

Plastic and wood are poor conductors of electric current, while copper and steel are good conductors of electric current. Which combination of materials would supply the most amount of resistance to an electric current? HINT: Which ones will FIGHT BACK the current the most????

• copper and steel

• plastic and copper

• plastic and wood

• wood and steel

Which of the following best describes electric voltage?

• the rate at which electric charges move

• the amount of electrical energy contained inside a battery

• the work needed to move an electric charge between two points

• the shock that a person experiences when he or she comes in contact with electricity

Some electric devices use direct current while others use alternating current. Which of the electric devices listed below uses mostly alternating current? HINT: Which one gets plugged into the wall to use AC?

• digital camera

• dishwasher

• Flashlight

• mp3 player

Most strings of outdoor lights are wired in a parallel circuit. Which of the following is the best reason why a string of outdoor lights should be wired in a parallel circuit and not a series circuit?

• Parallel circuits are safer to use than series circuits.

• The lights in a parallel circuit will light up brighter than the lights in a series circuit.

• If one light in the string burns out in a parallel circuit, the rest of the lights will continue to shine.

• You need to use more wires to construct a series circuit than a parallel circuit.

A student is building a simple circuit with a battery, light bulb, and copper wires. When she connects the wires to the battery terminals, the light bulb does not light up. Which of the following could explain why the bulb does not light?

• There is no energy source.

• The circuit is open.

• Copper wires do not conduct electric current.

• This circuit is too simple to light up a light bulb.

A GFCI is an example of what kind of electrical safety device?

• a frayed cord

• a lightning rod

• a parallel circuit

• a circuit breaker

Which of the following best describes a magnetic field?

• a measure of the length of a magnet

• the force that pushes two magnets away from each other

• an invisible region that surrounds the north pole of a magnet

• a region around a magnet in which you can measure magnetic forces