Question

Jenny and Fred both play a long note on their trombones. A stationary observer hears the sound increasing and decreasing repeatedly in
loudness. Which of these must be true?
A. The sound waves from the two trombones have slightly different frequencies.
B. The sound waves from the two trombones have the same frequency.
C. The sound waves from the two trombones have slightly different amplitudes.
D. The sound waves from the two trombones have the same wavelength.
E. The sound waves from the two trombones have slightly different velocities.

Answer 1

E=the sound waves from the trombones have slightly different velocity

Answer 2

The sound waves from the two trombones having slightly different frequencies is true.

What is Frequency?

This is referred to the number of waves that pass through a fixed place at a given point in time.

The sound waves increasing and decreasing repeatedly in loudness indicates difference in frequency which was why option A was chosen.

Read more about Frequency here https://brainly.com/question/254161

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