Physics · 2021
JEE Main · 3 August 2021, Shift 1 · Q18
An amount of 8 × 10^20 photons per second are emitting from a monochromatic source of light operated at 500 W, with 80 % efficiency. The wavelength…
An amount of $\displaystyle 8 \times 10^{20}$ photons per second are emitting from a monochromatic source of light operated at $\displaystyle 500$ W , with $\displaystyle 80 \%$ efficiency. The wavelength of the light is \_\_\_\_. (Take $\displaystyle h=6.63 \times 10^{-34} J s$ ).
Official answer
(4)
$\displaystyle 398$ nm
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JEE Main 2021 Physics question, with the answer from NTA’s final answer key. Where our answers come from.