An unknown tuning fork is sounded along with a tuning fork whose frequency is 256. Hz and a beat frequency of 3. Hz is heard. What is the frequency of the unknown tuning fork?
A) It must be 256 Hz.
B) It must be 253 Hz.
C) It could be either 253 Hz or 259 Hz; there is no way to tell.
D) It must be 259 Hz.

Question

Quizplus · Accepted Answer

The beat frequency is the absolute difference between the frequencies of two sounds. Since the beat frequency is 3 Hz, the unknown tuning fork could have a frequency either 3 Hz higher or 3 Hz lower than 256 Hz, making it either 253 Hz or 259 Hz.

An Unknown Tuning Fork Is Sounded Along with a Tuning