Question

A closed organ pipe of length $20cm$ is sounded with tuning fork in resonance. What is frequency of tuning fork? $(v=332m/s)$.

• A. $300Hz$
• B. $350Hz$
• C. $375Hz$
• D. $415Hz$

Answer 1

The correct option is D $415Hz$

In a closed organ pipe, resonance occurs at $\frac{\lambda }{4}$.

Given: $\frac{\lambda }{4}=0.2m$

$\Rightarrow \lambda =0.8m$

Frequency of tuning fork, $\upsilon =\frac{V}{\lambda }=\frac{332}{0.8}=415Hz$

Hence, option D is correct.