E&M (Unit 7) Part 1

Which of the following statements is true about electric forces?

• Electric forces cause objects to only attract each other.

• Electric forces cause objects to only repel each other.

• Electric forces cause objects to repel or attract each other.

• Electric forces have no effect on each other.

Which of the following materials is the best conductor of electricity?

• Wet skin

• Glass

• Dry air

• Rubber

Electric forces can be either repulsive or attractive, whereas gravitational force is always:

• Attractive

• Repulsive

• both options

• neither options

_____charges repel, whereas _____ charges attract.

• like, opposite

• opposite, like

• positive, negative

• negative, positive

A _____ is described as a device that converts chemical energy to electric energy.

• resistor

• lightbulb

• battery

• capacitor

An example of a voltage source is

• dry cell

• car battery

• generator

• rubbing a rubber rod with fur

• all possible options are correct

If the north pole of one magnet is brought near the south pole of another magnet, the poles will

• not interact

• repel

• attract

If you break a bar magnet in half, each half

• becomes a bar magnet with two poles.

• becomes unmagnetized.

• contains one magnetic pole.

Magnetic field strength is

• strongest close to a magnet.

• constant everywhere around a magnet.

• strongest far from a magnet.

If you put a small compass in a magnetic field, the compass will

• swing randomly.

• line up in a direction perpendicular to the magnetic field lines

• line up in a direction parallel to the magnetic field lines.

• seek electrical charge concentrations.