Unit 4 Exam Review

The force or push that causes electric charges to move is called .

• resistance

• voltage difference

• current

• static electricity

Electric charges always flow from areas to areas.

• positive, negative

• negative, positive

• positive, neutral

• neutral, negative

A material through which electrons do NOT flow easily is a(n) .

•  insulator

• fuse

• conductor

• circuit breaker

Which of the following statements about electric charge is true?  

• Objects must be touching on another to exert electrical force.

• Electrical forces act at a distance.

• Air cannot conduct electricity; it is conducted only by solid materials.

• Opposite electric charges always repel one another.

Mr. Robinson and his class are conducting an experiment.  The class needs to choose a good insulator.  Which of the following could be used as an insulator?

• plastic plate

• silver spoon

• copper wire

• gold necklace

Which of the following will increase the resistance of a wire?

•  using a thicker/ wider wire

• using a shorter wire

• increasing the temperature of the wire

• using silver instead of copper

What is the current produced by a 9-volt battery flowing through a resistance of 0.2 ohms?

•  1.8 amps

• 0.022 amps

• 45 amps

• 8.8 amps

Which two areas of physical science are closely related to the development of electric motors and generators?

• sound and light

• electricity and sound

• light and magnetism

• electricity and magnetism

Which of the following will decrease the strength of the magnetic field around a wire?

• increasing the current flowing through the wire

• using less loops around the iron core

• flipping the direction of the current flowing through the wire

• using a larger iron core

Silver has a resistance of 0.0198 ohms.  What voltage would produce a current of 100 amps?

• 1.98 V

• 0.000198 V

• 5,050 V

• 100.0198 V