When a certain photosensistive surface is illuminated with monochromatic light of frequency ν, the stopping potential for the photo current is – V0/2. When the surface is illuminated by monochromatic light of frequency ν/2, the stopping potential is – V0. The threshold frequency for photoelectric emission is :

Engineering

Physics

de Broglie Hypothesis and Dual Nature

Question

When a certain photosensistive surface is illuminated with monochromatic light of frequency ν, the stopping potential for the photo current is – V₀/2. When the surface is illuminated by monochromatic light of frequency ν/2, the stopping potential is – V₀. The threshold frequency for photoelectric emission is :

2 ν

$\frac{3}{2} ν$

$\frac{5 ν}{3}$

$\frac{4}{3} ν$

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eV_s = hν – $ϕ$

${\frac{- {eV}_{0}}{2} = hν - ϕ} \times 2 . ....... (1)$

$- eV = \frac{hν}{2} - ϕ . ......... (2)$

$0 = 2 hν - 2 ϕ - \frac{hν}{2} + ϕ$

$ϕ = \frac{3 hν}{2} \Rightarrow ν_{th} = \frac{3 ν}{2}$