JEE MAIN - Physics (2024 - 29th January Evening Shift - No. 19)

Two sources of light emit with a power of $$200 \mathrm{~W}$$. The ratio of number of photons of visible light emitted by each source having wavelengths $$300 \mathrm{~nm}$$ and $$500 \mathrm{~nm}$$ respectively, will be :
$$5: 3$$
$$3: 5$$
$$1: 5$$
$$1: 3$$

Explanation

$$\begin{aligned} & \mathrm{n}_1 \times \frac{\mathrm{hc}}{\lambda_1}=200 \\ & \mathrm{n}_2 \times \frac{\mathrm{hc}}{\lambda_2}=200 \\ & \frac{\mathrm{n}_1}{\mathrm{n}_2}=\frac{\lambda_1}{\lambda_2}=\frac{300}{500} \\ & \frac{\mathrm{n}_1}{\mathrm{n}_2}=\frac{3}{5} \end{aligned}$$

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