Question

A tuning fork arrangement (pair) produces 4beats/s with one fork of frequency 288 cps. A little wax is placed on the unknown fork and it then produces 2 beats/s. The frequency of the unknown fork is-

• A. $286cps$
• B. $292cps$
• C. $294cps$
• D. $288cps$

Answer 1

Answer: (B)

$292cps$

An unknown tuning fork is producing $4beats/sec$ with the fork of frequency $288cps$. This means that their frequencies differ by 4. The unknown fork might have frequency either $284cps$ or $292cps.$

On the application of wax, the number of beats reduce to $2$ per second which means they differ only by $2$ and it is only possible when the unknown fork has a greater frequency.