JEE Main 2022 · 30 Jun · Shift 1 · Physics Q48

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PhysicsSingle correct+4 / -1Question 48 of 90

A source of monochromatic light liberates $9\times10^{20}$ photon per second with wavelength 600 nm when operated at 400 W. The number of photons emitted per second with wavelength of 800 nm by the source of monochromatic light operating at same power will be :

12\times10^{20}

6\times10^{20}

9\times10^{20}

24\times10^{20}

Answer and worked solution

Official answer: A

Same power. Photon rate $\propto\lambda$ : $9\times10^{20}\times\frac{800}{600}=12\times10^{20}$ .

(A)

Topics:Photoelectric effect Photon momentum and radiation pressure

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JEE Main 2022 · 30 Jun · Shift 1, Physics question 48