Question
  1. Draw a graph showing variation of photocurrent with anode potential for a particular intensity of incident radiation. Mark saturation current and stopping potential.
  2. By how much would the stopping potential for a given photosensitive surface go up if the frequency of the incidentradiations were to be increased from $4\times10^{15}\text{ }\text{Hz}\text{ }\text{to}8\text{ }\times10^{15}\text{ }\text{Hz}$?

Answer

  1. Graph: 

  1. We know that $e\text{V}_0=hv-\phi$

$\therefore{e{\text{V}_1}}=hv_1-\phi$

and ${e{\text{V}_2}}=hv_2-{\phi}$

Increase in potential 

$\therefore\text{V}_2-\text{V}_1=\frac{h}{e}(v_2-v _1)$

$ =\frac{6.63\times10^{-34}}{1.6\times10^{-19}}(8\times10^{15}-4\times10^{15})\text{V}$

$=16.5\text{ }\text{V}$​​​​​​​

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