Q. If in a photoelectric cell, the wavelength of incident light is changed from 4000 Å to 3000 Å then change in stopping potential will be

JIPMER JIPMER 2015

Solution:

Change in stopping potential $= V_{s_2} -V_{s_1}$ $= \dfrac{hc}{e} \left[\dfrac{1}{\lambda_{2}}-\dfrac{1}{\lambda_{1}}\right]$ $= \dfrac{6.6 \times10^{-34}\times3\times10^{8}}{1.6 \times10^{-19}}\left[\dfrac{10^{10}}{3000}-\dfrac{10^{10}}{4000}\right]=1.03 V$

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