Respuesta :
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
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:
[tex]f_B = |f_1-f_2|[/tex]
In this problem, we are told that 20 beats per second are produced, so the beat frequency is
[tex]f_B = 20 s^{-1} = 20 Hz[/tex]
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 --> [tex]f_B = |38 Hz-63 Hz|=25 Hz[/tex] --> NO
B. 22 Hz and 42 Hz --> [tex]f_B = |22 Hz-42 Hz|=20 Hz[/tex] --> YES
C. 47 Hz and 55 Hz --> [tex]f_B = |47 Hz-55 Hz|=8 Hz[/tex] --> NO
D. 18 Hz and 26 Hz --> [tex]f_B = |18 Hz-26 Hz|=8 Hz[/tex] --> NO
So, the correct choice is
B. 22 Hz and 42 Hz