Section I: True/False. Choose the correct answer.

1. The human eye is most sensitive to blue light.

a. True
b. False

2. When a light wave hits a perfectly reflective surface and bounces off, the reflected wave will have a greater wavelength than the incident wave.

a. True
b. False

3. Sound waves move as transverse waves.

a. True
b. False

4. Sound waves move slower in water.

a. True
b. False

5. Light moves faster in water.

a. True
b. False

Section II: Multiple choice. Choose the correct answer.

1. If a 30º beam of light travels through air (n=1) into plexiglass (n=1.5), the angle of the beam inside the plexiglass will be

a. 30º
b. Less than 30º
c. More than 30º

2. A pendulum of length 40 cm with a 1 kg bob on the end has a period of 1.26 seconds. What would be the period if the mass was increased to 2 kg?

a. 2.52 seconds
b. 0.63 seconds
c. 1.26 seconds
d. 2 seconds

3. What is the period of a 2 cm wave that travels 4 meters in 16 seconds?

a. 12.5 seconds
b. 0.08 seconds
c. 0.25 seconds
d. 6.5 seconds

4. The slits on most polarizing sunglasses are oriented in what direction?

a. Vertical
b. Horizontal

5. Which of the following is an acceptable "equation" to create magenta?

a. Red+blue-green
b. Red+green-blue
c. Yellow+red+green
d. Blue+yellow-green

Section III: Solve. Show all work!

1. The original Tacoma Narrows Bridge collapsed on November 7, 1940, just barely over four months after it was opened to the public. It is considered to be a prime example of failed engineering. It was a very long, very thin bridge without the needed girders for support underneath (fortunately, the remodeled version is still going strong). The common explanation for the Tacoma Narrows Bridge collapse is what is known as forced resonance. Explain, in your own words, what forced resonance means in this situation.

2. Consider this image of a prism from a famous album cover (actually the back cover). Suppose that the white light ray is entering from the right side of the prism and exiting from the left. Name two things that are incorrect about this image.

3. The Moon's gravitational pull is about 1/6th that of Earth's. Suppose a pendulum of length 1 meter has a period of 2 seconds on Earth. An astronaut on the Moon wants to create a pendulum that will have the same period. Knowing the Moon's gravity is about 1/6th of Earth's, will the astronaut's pendulum have a longer or shorter string? What would be the length of the string?

4. Explain what happens when a star's light is either redshifted or blueshifted.