Science Unit B, Chapter 3

1.

1 point

Which situation is NOT a safety problem?

Touching an electric toaster with wet hands

Operating an electric heater near window curtains

Limiting the number of appliances plugged into one outlet

Running a vacuum cleaner with a cut in the electric cord

2.

1 point

The northern lights are caused by the Earth's _________________________.

3.

1 point

You hold two south poles of two magnets near each other. The poles will

repel each other.

spin clockwise.

spin counterclockwise.

attract each other.

4.

1 point

When you walk across a wool rug, you may feel a shock when you tough the hand of a nearby friend. This happens because

your body picked up positive charges from the rug as you walked across it.

your body picked up positive charges from your friend's hand.

your body picked up negative charges from the rug as you walked across it.

your body picked up negative charges from your friend.

5.

1 point

Which of these statements about a parallel circuit is correct?

It is more dangerous to use than a series circuit.

It allows you to turn appliances on and off separately.

It can power more appliances than a series circuit.

It requires more energy to work.

6.

1 point

Which of these statements about Earth's magnetism is correct?

Earth's magnetic pull is strongest at the equator.

Earth has a magnetic field and two poles.

Magnetism pulls Earth toward the sun.

Magnetism keeps Earth in orbit.

7.

1 point

If a magnet is allowed to swing freely, the north-seeking pole will point

up.

down.

north.

south.

8.

1 point

An ________________ is created when electric current flows through a wire.

9.

1 point

If you connect too many appliances to one circuit, the wires can

blow up.

generate more power and heat.

overheat and cause a fire.

give you a shock if you touch them.

10.

1 point

The flow of negative charges through matter is called ____________.

11.

1 point

You should NOT use electrical appliances near water because water

is a good insulator.

can make electric wires heat up.

can rust electric wires.

conducts electricity.

12.

1 point

Which of these substances is the best conductor of electricity?

air

rubber

plastic

metal

13.

1 point

If you plug too many appliances into one electric outlet, you can cause an ______________.

14.

1 point

Two balloons have negative charges. If you put them close to one another, the balloons will

float upwards.

pull toward each other.

push away from each other.

stick together firmly.

15.

1 point

Electric wire is coated with plastic or rubber because these materials

melt very slowly.

conduct the flow of electricity.

are inexpensive and easy to make.

are good resistors.

16.

1 point

A machine that produces electricity is called a ________________.

17.

1 point

The invention of the compass showed that Earth acts like a giant ___________.

18.

1 point

The fact that electromagnets can be turned on and off easily means that they are

dangerous to use in the house.

a poor source of electric power.

safe to use around water.

useful in household appliances.

19.

1 point

When you rub two balloons together, ____________ can move from one to the other.

20.

1 point

Electric current flows through a circuit only when it is _____________.

21.

1 point

Every time you turn on a light, you

open a closed circuit.

close an open circuit.

add a source of power to a circuit.

remove a source of power from a circuit.

22.

1 point

When two objects have different electric charges, they

pull toward each other

gain energy

lose matter

push away from each other

23.

1 point

Electric current passes easily through a

resitor

insulator

conductor

switch

24.

1 point

Electric generators can get their power from all of these EXCEPT

rushing water.

lightning.

wind.

burning oil.

25.

1 point

You have built a series circuit containing two light bulbs, which are both lit. If you remove one of the bulbs, what happens to the other bulb?

It remains lit.

It becomes brighter.

It burns out.

It goes out.

26.

1 point

A pole is the part of a magnet that

has the strongest magnetic pull.

has the strongest negative charge.

has the strongest positive charge.

has the weakest charge.

27.

1 point

Electric current is the flow of

positive charges through matter.

negative charges through matter.

magnetism through matter.

energy and light through matter.