Question

A tuning fork of frequency 480 Hz produces 10 beats per second when sounded with a vibrating sonometer string. What must have been the frequency of the string if a slight increase in the tension of the string produces fewer beats per second than before?

Solution

Correct option is

470 Hz

The frequency of the string is either V1 = 480 – 10 = 470 Hz or V2 = 480 + 10 = 490 Hz. Now, the frequency of wire   So, when tension is slightly increased, the frequency of the wire also slightly increases. Hence fewer beats will be produced if the frequency of the wire is 470 Hz.

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