Science Unit 7 Review

1. Which of these materials is a conductor?

• rubber
• chalk
• gold
• glass

2. What is one use for an insulator?

• It slows down the flow of electric current to produce heat and light.
• It stores electric energy for later use.
• It allows electric current to flow through it.
• It makes electrically charged objects safe to handle.

3. Electric current cannot flow in a series circuit if

• the circuit contains an insulator.
• there is a break in the circuit.
• the circuit contains a resistor.
• the circuit has only one loop in it.

4. One example of a resistor is

• a power cord
• a parallel circuit
• a battery
• a filament

5. What will happen in a parallel circuit if one of its loops is broken?

• electric current will not flow through any of the loops
• electric current will still flow through the broken loop
• electric current will still flow through the unbroken loops
• the energy source will stop providing energy to move electric charges

6. Which of the following is caused by the energy of motion?

• resistor
• friction
• conductor
• filament

7. Which of the following uses resistors to transform electricity into heat?

• a toaster
• a car engine
• a gas stove
• a wind turbine

8. Which of the following groups of materials make the best insulators?

• Gold, wood, copper
• Copper, plastic, gold
• Rubber, glass, plastic
• Graphite, glass, wood

9. An engineer is designing a new type of electrical wire. He wants to make sure that electricity will flow through the wire very easily. He tests four materials and performs each test several times to make sure that the results are accurate. Based on the results in the table, which material would be best for the new type of electrical wire?

• Material A
• Material B
• Material C
• Material D

10. Why is copper classified as a conductor?

• Electric current travels easily through copper.
• Copper may gain or lose electric charges.
• Copper resists the flow of electrical current.
• None of the other answer choices.