11.

Which type of mirror always gives an image which is the same size as the object?

flat mirror

concave mirror

convex mirror

diffuse mirror

12. An electromagnetic wave is:

a bit of radiation that could cause health problems.

a two-dimensional wave that does not need a medium to travel.

a sonar wave that travels at about the speed of light.

all light that is not visible to the human eye.

13. Magenta light shines on a green shirt. What color of light would you expect to be reflected?

Blue

None

Cyan

Green

14. Why do you think blacksmiths must have such hot fires to forge steel?

Because metals are able to deflect heat and so need a hot fire.

Because metals absorb lots of heat, and so need a hot fire.

Because metals are naturally cold, and so need a hot fire.

Because metals are brittle and so need a hot fire.

15. The Celsius and Kelvin scales are useful because:

they sound more official outside of the U.S.A.

there are two of them.

they are based off natural physical phenomena.

Fahrenheit is an old scale.