The ratio of frequencies of oscillations of two simple pendulums is $3: 4$, then their lengths are in the…
The ratio of frequencies of oscillations of two simple pendulums is $3: 4$, then their lengths are in the ratio
- $16: 9$
- $9:16$
- $\sqrt{3}: \sqrt{4}$
- $\sqrt{4}: \sqrt{3}$
Solution
Frequency of simple pendulum is given by
$\begin{aligned}
\mathrm{f} &=\frac{1}{2 \pi} \sqrt{\frac{\mathrm{g}}{\ell}} \quad \therefore \frac{\mathrm{f}_{1}}{\mathrm{f}_{2}}=\sqrt{\frac{\ell_{2}}{\ell_{1}}} \\
\therefore \frac{3}{4} &=\sqrt{\frac{\ell_{2}}{\ell_{1}}} \quad \text { or } \quad \frac{9}{16}=\frac{\ell_{2}}{\ell_{1}} \\
\therefore \frac{\ell_{1}}{\ell_{2}} &=\frac{16}{9}
\end{aligned}$
Asked in: MHT CET 2020 (14 Oct Shift 1)
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