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Beat Frequencies

Beat Frequencies. Assume two waves are superpositioned Amplitudes are the same Frequencies & wavelengths are different Use fact that. to yield. Groups and phases. Cosine portion defines “envelope” within which sine portion oscillates Envelope moves with a speed.

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Beat Frequencies

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  1. Beat Frequencies • Assume two waves are superpositioned • Amplitudes are the same • Frequencies & wavelengths are different • Use fact that to yield

  2. Groups and phases • Cosine portion defines “envelope” within which sine portion oscillates • Envelope moves with a speed • Individual sine waves move with a speed of

  3. Beat frequency is the frequency associated with the group packet • As frequencies get closer together, beat frequency goes down • Beat frequencies are often used with Doppler shifts to determine speed

  4. 60 0 of 1 Answer Now You have two tuning forks that have a beat frequency of 2 Hz with respect to each other. One of them has a frequency of 440 Hz, but you do not know the frequency of the other. You place a small piece of clay on the other, an amount just capable of changing the beat frequency by 1 Hz, and you repeat the experiment. This time the beat frequency is 3 Hz. From this information, what is the frequency of the other tuning fork (when it has no clay on it)? • 442 Hz. • 443 Hz. • 438 Hz. • 437 Hz.

  5. 30 0 of 1 Answer Now You have two tuning forks that have a beat frequency of 2 Hz with respect to each other. One of them has a frequency of 440 Hz, but you do not know the frequency of the other. You place a small piece of clay on the other, an amount just capable of changing the beat frequency by 1 Hz, and you repeat the experiment. This time the beat frequency is 3 Hz. From this information, what is the frequency of the other tuning fork (when it has no clay on it)? • 442 Hz. • 443 Hz. • 438 Hz. • 437 Hz.

  6. A beat frequency of 150 Hz is produced by an ultrasonic echo mixed with its original frequency of 2.50 MHz after being reflected from the heart wall of a patient. What is the speed of the wall? Take the speed of sound in the body as being1540 m/s.

  7. 30 0 of 1 Answer Now What is the speed of the heart wall? • 7.70 x 102 m/s • 1,49 x 103 m/s • 4.62 x 10-2 m/s • 9.24 x 10-2 m/s

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