Title: Summative Assessment
Course: MNPCC Physics > Section: Mechanical Waves

Use this quiz to see if you learned everything you were supposed to during the unit.

Q: What is the amplitude of the wave depicted here?
- 1.5 (Correct.)
- 3 (That is twice the amplitude.)
- 8 (That is the wavelength.)
A: 1.5
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: How does the wavelength of a sound when the receiver is moving away from the source compare to the wavelength if the source and receiver are stationary?
- The wavelength is longer.
- The wavelength is shorter.
- The wavelength does not change.
A: The wavelength is longer.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: A light flickers 30 times in one second.  What is the frequency of the light in Hertz?
- 30 (Correct.)
- 0.03 (This is the period, not the frequency.)
- 1 (Not sure how you arrived at this.)
- 15 (Not sure how you arrived at this.)
A: 30
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: What type of interference gives rise to antinodes in standing waves?
- Both constructive and destructive interference happens at these sites.
- Constructive interference only.
- Destructive interference only. (The shapes of the pulses will be preserved.)
A: Both constructive and destructive interference happens at these sites.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: If one firecracker going off registers 100 decibels.  How many firecrackers would it take to register 120 decibels?
- 100
- 20
- 2
- 10
A: 100
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: What happens to the frequency of a sound in order for the pitch to go up 2 octaves?
- It goes up 4 times.
- It goes up 2 times. (Frequency doubles for each octave.)
- It goes up 2 hertz. (Frequency doubles with each octave.)
- It goes up 4 hertz. (Frequency doubles with each octave.)
A: It goes up 4 times.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: What is the velocity in m/s of the wave depicted here, if a crest can be seen going by every 4 seconds and each block represents 1 m?
- 1 (Correct.)
- 16 (4 seconds is the period not the frequency.)
- 2 (The wavelength is 4 not 8.)
- 32 (You have the wavelength and the frequency wrong.)
A: 1
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: How does the amount of air that reaches your ear from mouth compare when I shout compared to when I whisper to you from across a large room.
- The amount is the same. (Correct, in both cases there is none.)
- More reaches when you shout. (Waves only transfer energy, not matter.)
- More reaches when you whisper. (Waves transfer energy, not matter.)
- Nothing is actually being transported.
A: The amount is the same.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: What type of wave is sound?
- Longitudinal (compression). (Correct.)
- Transverse. (Air cannot have transverse waves.)
- It can be either type. (Sound is always a longitudinal (compression).)
A: Longitudinal (compression).
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: What is the wavelength of the wave shown here?
- 1.8 (Correct.)
- 2 (It is just under 2.)
- 0.9 (That is only half.)
- 1 (Half of it is a little under 1.)
- 9 (That is the length of 5 waves.)
A: 1.8
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: What happens to the frequency of a note played by an instrument if the wavelength is cut in half.
- The frequency will double.
- The frequency will be cut in half. (They are inversely related.)
- The frequency will not change.
A: The frequency will double.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: What happens to the velocity of the wave on a guitar string when the length of the string is cut in half?
- The velocity does not change.
- The velocity is cut in half. (Velocity only depends on the material.)
- The velocity is doubled. (Velocity only depends on the material the wave is traveling through.)
A: The velocity does not change.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: What happens to the velocity of the wave on a guitar string when the length of the string is cut in half?
- The velocity does not change.
- The velocity is cut in half. (Velocity only depends on the material.)
- The velocity is doubled. (Velocity only depends on the material the wave is traveling through.)
A: The velocity does not change.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: What happens to the velocity of the wave on a guitar string when the string is loosened?
- The velocity goes down.
- The velocity goes up. (Since this causes a drop in pitch without changing the wavelength, the velocity must be going down.)
- The velocity does not change. (The property of the material changes, so the velocity changes.)
A: The velocity goes down.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: What quality of the wave must be matched up to the size of an object in some multiple in order for a sound to resonate on the object?
- Wavelength
- Frequency
- Amplitude
- Velocity
A: Wavelength
If right: Your answer is correct.
If wrong: Your answer is incorrect.