When the wavelength of radiation falling on a metal is changed from 500 nm to 200 nm, the maximum kinetic energy of the photoelectrons becomes three times larger. The work function of the metal is close to :
Solution
K<sub>1</sub> = ${{hc} \over {500}} - {\phi _0}$
<br><br>K<sub>2</sub> = ${{hc} \over {200}} - {\phi _0}$
<br><br>$\because$ K<sub>2</sub> = 3K<sub>1</sub>
<br><br>$\Rightarrow$ $$3\left[ {{{hc} \over {500}} - {\phi _0}} \right] = \left[ {{{hc} \over {200}} - {\phi _0}} \right]$$
<br><br>$\Rightarrow$ $\phi$<sub>0</sub> = 0.61 eV
About this question
Subject: Physics · Chapter: Dual Nature of Matter and Radiation · Topic: Photoelectric Effect
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