8 Electricity Test Unit 2 L1,2,3

1. Which of the following best describes electric charge?

• A. a force that causes objects to heat up
• B. a high-voltage material that can cause damage to objects
• C. a fundamental property that causes electric and magnetic interactions
• D. a particle that moves freely through matter and causes static electricity to build up on objects

2. Peter’s teacher tells him that he should not place his electric stereo near the edge of a pool because the water in the pool is a conductor. What does she mean when she says that the water is a conductor?

• A. Water is a type of electrical energy.
• B. Water damages electric circuits.
• C. Electric charges cannot flow without water.
• D. Electric charges move through the water in the pool

3. 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?

• A. The charges disappeared.
• B. The charges transferred to another object.
• C. The charges switched from negative to positive.
• D. The charges broke apart into smaller positive and negative particles.

4. 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?

• A. a conductor
• B. an insulator
• C. a semiconductor
• D. a tube

5. The following image shows two circular objects. Each object has an electric charge, as shown: What will happen to these objects when they are placed near each other?

• A. The objects will remain still.
• B. The objects will both move to the left.
• C. The objects will move towards each other.
• D. The objects will move away from each other

1. The following table describes the resistance of two different wires. Based on this table, which of the following is most likely true?

• A. Wire A is longer and thinner than wire B.
• B. Wire A is shorter and thicker than wire B.
• C. Wire A is a poor conductor of electric current.
• D. Wire B is a good conductor of electric current.

2. 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?

• A. copper and steel
• B. plastic and copper
• C. plastic and wood
• D. wood and steel

3. Which of the following best describes electric voltage?

• A. the rate at which electric charges move
• B. the amount of electrical energy contained inside a battery
• C. the work needed to move an electric charge between two points
• D. the shock that a person experiences when he or she comes in contact with electricity

4. What is electric current?

• A. the rate at which electric charges pass a given point
• B. a material’s opposition to the flow of electric charge
• C. the number of electric charges that pass a given point
• D. the amount of work to move a unit of electric charge between two points

5. Some electric devices use direct current while others use alternating current. Which of the electric devices listed below uses mostly alternating current?

• A. digital camera
• B. dishwasher
• C. flashlight
• D. mp3 player