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Physics · PYQ NEET UG 2021
हिन्दीAn electromagnetic wave of wavelength '\( \lambda \)' is incident on a photosensitive surface of negligible work function. If '\( m \)' mass is of photoelectron emitted from the surface has de-Broglie wavelength \( \lambda_d \) then:
Correct answer · Option 2
\( \lambda = (\frac{2mc}{h}) \lambda_d^2 \)
Explanation
Energy of photon \( E = \frac{hc}{\lambda} = \frac{p^2}{2m} \). De-Broglie wavelength \( \lambda_d = \frac{h}{p}\Rightarrow p = \frac{h}{\lambda_d} \). Substituting: \( \frac{hc}{\lambda} = \frac{h^2}{2m \lambda_d^2} \Rightarrow \lambda = (\frac{2mc}{h}) \lambda_d^2 \).
