Question

Ms. Knuth places a stick in a pond. When she looked down at the stick, it appeared to be broken or bent at the point where the stick entered the water. This was caused by:

a
A refraction of light from the water.
b
Diffraction of light waves around the stick.
c
Refraction of light waves passing from air into water.
d
Reflection of light waves passing from air into water.
Question 5 (1 point)
A diagram of a wave is shown below.



What is the amplitude of the wave?



a
10 cm
b
50 cm
c
20 cm
d
6 cm
Question 6 (1 point)
How are wavelength and frequency related?

a
If the speed between the crests of the waves decreases, the frequency increases.
b
If the speed between the crests of the waves increases, the frequency increases.
c
If the distance between the crests of the waves decrease, the frequency decreases.
d
If the distance between the crests of the waves increase, the frequency decreases.

Answer 1

1) c — Refraction of light waves passing from air into water. Light bends at the interface because the speed changes in water.

2) c — 20 cm. Amplitude is the maximum displacement from the equilibrium (half the peak-to-trough distance).

3) d — If the distance between the crests (wavelength) increases, the frequency decreases. (Since v = f·λ, for a given wave speed v, f = v/λ.)