Q129 / 150 · MHT CET 2024 (10 May Shift 1) · Physics
When the listener moves towards stationary source with velocity ' $\mathrm{V}_1$ ', the apparent frequency of emitted note is ' $F_1$ '. When observer moves away from the source with velocity ' $\mathrm{V}_1$ ', apparent frequency is ' $\mathrm{F}_2$ '. If' V is the velocity of sound in air and $\frac{F_1}{F_2}=2$ then $\frac{V}{V_1}$ is
- A2
- Correct answerB3
- C4
- D5
Solution
$\begin{aligned}
& F_1=F\left(\frac{V+V_1}{V}\right) \\
F_2 & =F\left(\frac{V-V_1}{V}\right) \\
\therefore \quad & \frac{F_1}{F_2}=\left(\frac{V+V_1}{V-V_1}\right)=2 \\
\therefore \quad & \frac{V}{V_1}=3
\end{aligned}$
...(given)
Hence, the correct answer is option: 'B'.