What is the beat frequency when a 494 Hz tuning fork and 499 are sounded together?

To calculate the beat frequency, we subtract the frequency of the tuning fork (494 Hz) from the frequency of the sound (499 Hz).

$$f_{beat} = |f_1 - f_2 |$$

$$f_{beat} = |499 Hz - 494 Hz | = 5 Hz$$

Therefore, the beat frequency is 5 Hz.