Question

Two tuning forks A and B vibrating simultaneously produce $5$ beats. Frequency of B is $512$. it is seen that of one arm of A is filed, then the number of beats increases. Frequency of A will be

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

Answer 1

The correct option is C $517$

Beat frequency is difference in frequencies

filing increases the frequency so.

$\begin{array}{c}{\eta }_A-{\eta }_B=5\\ {\eta }_A-512=5\\ {\eta }_A.512+5=517Hz\end{array}$

Option C.