If the frequency of a wave is increased by $25 \%$, then the change in its wavelength is (medium not changed)
If the frequency of a wave is increased by $25 \%$, then the change in its wavelength is (medium not changed)
- $20 \%$ increase
- $20 \%$ decrease
- $25 \%$ increase
- $25 \%$ decrease
Solution
Frequency of wave, $f \mu \frac{1}{\lambda}$
$\therefore \frac{\lambda_2}{\lambda_1}=\frac{\mathrm{f}_1}{\mathrm{f}_2}=\frac{\mathrm{f}_1}{1.25 \mathrm{f}_1}=\frac{4}{5} \therefore \% \Delta \lambda=\frac{\lambda_1-\lambda_2}{\lambda_1} \times 100$
$=\frac{\lambda_1-\frac{4}{5} \lambda_1}{\lambda_1} \times 100=20 \%$ decrease
Asked in: AP EAMCET 2024 (20 May Shift 1)
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