When a certain metallic surface is irradiated with monochromatic light wavelength λ , the stopping potential for photoelectric current is 3 V 0 . When the same surface is irradiated with light of wa

Question

When a certain metallic surface is irradiated with monochromatic light wavelength $λ$ , the stopping potential for photoelectric current is $3 V_{0}$ . When the same surface is irradiated with light of wavelength $2 λ$ , the stopping potential is $V_{0}$ . The threshold wavelength for the given surface is

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Answer:

A

Solution:

$3 e V_{0} = \frac{h c}{λ} - ϕ e V_{0} = \frac{h c}{2 λ} - ϕ$

Elimination gives

$ϕ = \frac{h c}{4 λ} λ_{th} = 4 λ$

TestHub · Accepted Answer

​ 3 e V 0 ​ = λ h c ​ − ϕ ​ e V 0 ​ = 2 λ h c ​ − ϕ ​ Elimination gives ​ ϕ = 4 λ h c ​ ​ λ th ​ = 4 λ ​

Physics - Modern Physics Question with Solution | TestHub

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