Question

A tuning fork $A$ of frequency $512Hz$ produces $5$ beats per second when sounded with another tuning fork $B$ of unknown frequency. If $B$ is located with wax the number of beats is again $5$ per second. The frequency of the tuning fork $B$ before it was loaded is

• A. $502Hz$
• B. $507Hz$
• C. $517Hz$
• D. $522Hz$

Answer 1

The correct option is C $517Hz$

Frequency of $A$ , $n=512Hz$

Number of beats$/$sec, $m=5$

$\therefore$ Frequency of B, $n^{\prime }=512\pm 5=517or505$

On loading $B$, its frequency decreases from $517$ to $505$, so that number of beats per second remains $5$.

Hence, frequency of $B$, when not loaded $=517Hz$