1. Move your hand up and down more quickly as you generate the pulse.
Which of the following actions would make a pulse travel faster down a stretched string?
Move your hand up and down more quickly as you generate the pulse.
Move your hand up and down a larger distance as you generate the pulse.
Use a heavier string of the same length, under the same tension.
Use a lighter string of the same length, under the same tension.
Use a longer string of the same thickness, density and tension.
STT20.2

2. Move your hand up and down more quickly as you generate the pulse.
Which of the following actions would make a pulse travel faster down a stretched string?
Move your hand up and down more quickly as you generate the pulse.
Move your hand up and down a larger distance as you generate the pulse.
Use a heavier string of the same length, under the same tension.
Use a lighter string of the same length, under the same tension.
Use a longer string of the same thickness, density and tension.
STT20.2
v = √(F/μ), so a decrease in μ results in an increase in speed

3. What is the frequency of this traveling wave?
10 Hz
5 Hz
2 Hz
0.2 Hz
0.1 Hz
STT20.3

4. What is the frequency of this traveling wave?
10 Hz
5 Hz
2 Hz
0.2 Hz
0.1 Hz
STT20.3
v = λf, so f = v/λ = 50/10 = 5 Hz

5. A light wave travels through three transparent materials of equal thickness. Rank is order, from the largest to smallest, the indices of refraction n1, n2, and n3.
n2 > n1 > n3
n3 > n1 > n2
n1 > n2 > n3
n3 > n2 > n1
n1 = n2 = n3
STT20.5

6. A light wave travels through three transparent materials of equal thickness. Rank is order, from the largest to smallest, the indices of refraction n1, n2, and n3.
n2 > n1 > n3
n3 > n1 > n2
n1 > n2 > n3
n3 > n2 > n1
n1 = n2 = n3
n = c/v and v = λf, so n = c/(λf). The frequency and speed of light are fixed, so the observed wavelength is the only variable in the media.
STT20.5

7. Amy and Zack are both listening to the source of sound waves that is moving to the right. Compare the frequencies each hears.
STT20.6
fAmy < fZack
fAmy = fZack
fAmy > fZack

8. Amy and Zack are both listening to the source of sound waves that is moving to the right. Compare the frequencies each hears.
Whether observed frequency increases, decreases, or stays the same depends on the relative motion of source and receiver. Amy and the source are not moving with respect to one another so the observed frequency is the source frequency. Zack and the source are moving toward one another, so the observed frequency is higher than the source frequency.
STT20.6
fAmy < fZack
fAmy = fZack
fAmy > fZack