1) An object is placed 12 cm in front of a concave mirror. The mirror forms a real inverted image that is the similar size as the object, also at 12 cm in front of the mirror. The focal length of the mirror is

1) 3.0 cm

2) 4.0 cm

3) 6.0 cm

4) 12 cm

5) 24 cm

2) At a point of observation, the time among successive crests of a passing wave is 0.2 s. Which of the following must be true of the wave?

1) Its wavelength is 0.2m

2) Its wavelength is 5m

3) Its period is 5 s

4) Its frequency is 5 Hz

5) Its velocity of propagation is 5m/s

3) Which of the following experimental observations provides the best support for the statement "Light behaves like a wave?"

1) Light can be reflected by a mirror

2) Light is bent by a gravitational field.

3) Light is scattered when passing through smoke

4) White light can be broken into component colours by a prism

5) Monochromatic light forms bright and dark bands after passing during two narrow slits