Question

Fifty six tuning forks are arranged in a series such that each fork gives 6 beats per second with the preceding one. Assuming the frequency of the last fork to be double of the first fork, the frequency of the last fork should be

• A. 220 Hz
• B. 330 Hz
• C. 440 Hz
• D. 660 Hz

Hint:

Beat frequency = difference between frequencies of two forks.

Answer 1

The Correct Option is D

Step 1: Let first frequency = $f$, last frequency = $2f$. With 56 forks, there are 55 intervals. Each interval gives 6 beats, so frequency increases by 6 Hz each step.

Step 2: $2f = f + 55 × 6 → f = 330$ Hz. Last frequency = $2f = 660$ Hz.