Question

If two tuning forks $A$ and $B$ are sounded together, they produce $4$ beats per second. $A$ is then slightly loaded with wax, they produce $2$ beats when sounded again. The frequency of $A$ is $256$. The frequency of $B$ will be

• A. $250$
• B. $260$
• C. $262$
• D. $252$

Answer 1

The correct option is D $252$

Given, frequency of $A\text{i}s\Rightarrow N_A=256$.
$A\text{a}ndB$ are sounded together, $x=4bps$

Frequency of $B=?$

Now wax decreases the frequency of tuning fork. Waxing frequency 𝐴 has reduced such a way that $4bps$ per second.

$N_A-N_B=x$

$\Rightarrow N_B=N_A-x$

$\Rightarrow N_B=256-4$

$\Rightarrow N_B=252Hz$.

Final Answer: $\left(b\right)$