Quiz 1

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Quiz 2

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Quiz 3

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Quiz 4

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Keep in mind, the actual path difference was 5 m – 4 m = 1 m. The wavelength is 2 m, so this distance is half a full cycle, or pi radians.

Quiz 5

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Pi radians phase difference corresponds to perfect destructive interference.

Quiz 6

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Congratulations to the 41 people who got this correct! The answer is E!!!

Beats are loud sounds separated by soft sounds. If you blindly trust the equation for beat frequency, you will get 80 Hz. But you need to think about this answer. Does it make sense? Do you expect to count 80 loud sounds separated by soft sounds every second? This does not make sense! Beats only occur when the two waves are close to the same frequency.

Quiz 7

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Good. This is correct – you will hear one beat per second.