An electromagnetic wave of wavelength λ is incident on a photosensitive surface of negligible work function. If m mass is of photoelectron emitted fro - Physics MCQ NEET 2021 2026 | ExamTest.live

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An electromagnetic wave of wavelength λ is incident on a photosensitive surface of negligible work function. If m mass is of photoelectron emitted from the surface has de-Broglie wavelength λ_{d}, then:

Solution & Step-by-step Explanation

Kinetic energy of photoelectron K = \frac{h c}{λ} (since work function ϕ = 0).Also, K = \frac{p ^{2}}{2 m}, where p = \frac{h}{λ _{d}} . K = \frac{( h / λ _{d} ) ^{2}}{2 m} = \frac{h ^{2}}{2 m λ _{d}^{2}} Equating both: \frac{h c}{λ} = \frac{h ^{2}}{2 m λ _{d}^{2}} \frac{c}{λ} = \frac{h}{2 m λ _{d}^{2}} \Rightarrow λ = \frac{2 m c λ _{d}^{2}}{h} λ = (\frac{2 m c}{h}) λ_{d}^{2}

Try it yourself before checking the explanation above.

An electromagnetic wave of wavelength λ is incident on a photosensitive surface of negligible work function. If m mass is of photoelectron emitted from the surface has de-Broglie wavelength λ_{d}, then:

λ = (\frac{2 m c}{h}) λ_{d}^{2}

λ = (\frac{2 h}{m c}) λ_{d}^{2}

λ = (\frac{m c}{2 h}) λ_{d}^{2}

λ_{d} = (\frac{2 m c}{h}) λ^{2}

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