UnethicalPsych
Answered

If 20 beats are produced within one second, which of the following frequencies could possibly be held by two sound waves traveling through a medium along a common path at the same time?

A38 Hz and 63 Hz
B22 Hz and 42 Hz
C47 Hz and 55 Hz
D18 Hz and 26 Hz

Verified Answer :

Hagrid

The right answer for the question that is being asked and shown above is that: "B. 22 Hz and 42 Hz." If 20 beats are produced within one second, the frequencies that could possibly be held by two sound waves traveling through a medium along a common path at the same time is B. 22 Hz and 42 Hz 

skyluke89

Answer:

B. 22 Hz and 42 Hz

Explanation:

The beat is an interference pattern which occurs when two waves of slightly different frequencies meet each other. The beat is heard as a periodic variation, whose frequency (called beat frequency) is equal to the absolute value of the difference between the frequencies of the individual waves:

\(f_B = |f_1-f_2|\)

In this problem, we are told that 20 beats per second are produced, so the beat frequency is

\(f_B = 20 s^{-1} = 20 Hz\)

Therefore, we must find the two waves which have a difference in frequency equal to this value, 20 Hz. Let's see each choice:

A. 38 Hz and 63 Hz  --> \(f_B = |38 Hz-63 Hz|=25 Hz\) --> NO

B. 22 Hz and 42 Hz  --> \(f_B = |22 Hz-42 Hz|=20 Hz\) --> YES

C. 47 Hz and 55 Hz  --> \(f_B = |47 Hz-55 Hz|=8 Hz\) --> NO

D. 18 Hz and 26 Hz --> \(f_B = |18 Hz-26 Hz|=8 Hz\) --> NO

So, the correct choice is

B. 22 Hz and 42 Hz


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