Electric charges that are different

attract each other.
repel each other. ****
exist in pairs.
do not interact.

Magnetic field lines around a bar magnet

are only perpendicular to the magnet.
spread out from one pole and curve around to the other. ****
cross back and forth over one another.
are perfectly straight.

Which of the following would decrease the magnetic field around a wire?

decreasing the current
reversing the poles of the wire
looping a section of the wire into a solenoid ****
increasing the current

What device transforms electrical energy into mechanical energy?

an electromagnet
an electric motor ****
a generator
a solenoid

A device used to open and close an electric circuit is a(n)

light bulb.
energy source.
switch. ****
resistor.

According to Ohm’s law, resistance is equal to voltage divided by

time.
conduction. ****
current.
potential.

In a series circuit with three bulbs,

the remaining two bulbs will go out if one bulb burns out.
the remaining two bulbs are not affected if one bulb burns out.
the brightness of the light bulbs does not change if more bulbs are added. ****
a switch is never used.

The strength of the force of gravity depends on

the masses of the objects and their speeds.
the masses of the objects and the distance between them.
the weight of the objects and their speeds.
the masses of the objects and their weights. ****

9. According to Ohm’s law, what is the resistance of a light bulb if the applied voltage is
9.0 V and the current is 0.30 amps?

0.033 ohms
2.7 ohms
30 ohms****
8.7 ohms