Question

The threshold frequency of a metal is f when the light of frequency 2f is incident on the metal plate the maximum velocity of the photoelectron is V1 when the frequency of incident radiation is increased to 5f the maximum velocity of photoelectron is V2. Find the ratio V1:V2?

Answer 1

Solution:

Using Einsteins photoelectric equation

E= W$_{0}$ +K $_{max}$

when light of frequency  2f is incident on a metal plate

1/2 mv$_{max}$$^{2}$ = h (v-v$_{0}$

1/2 mv$_{1}$$^{2}$  = h( 2f-f)  = hf

when light of frequency 5f is incident on a metal plate

1/2 mv$_{1}$$^{2}$ = h( 5f-f) = 4hf

$\frac{v^{2} _{1} }{v^{2} _{2} }  = \frac{1}{4}$

=> $\frac{v_{1} }{v_{2} } = \frac{1}{2}$

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@GauravSaxena01