Physics · 2021
JEE Main · 4 August 2021, Shift 2 · Q29
A light source of 25.1 mW emits 2 × 10^16 photons per second. An unknown metal is brought in front of this light source from which electrons of speed…
A light source of $\displaystyle 25.1$ mW emits $\displaystyle 2 \times 10^{16}$ photons per second. An unknown metal is brought in front of this light source from which electrons of speed upto $\displaystyle 10^6 \mathrm{~m} / \mathrm{s}$ are emitted upon the incidence of the photons from the light source. The work function of the unknown metal is \_\_\_\_ eV.
Official answer
5
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