Dual Nature Of Light Question 249
Question: The work function of a metal is $ 1.6\times {{10}^{-19}} $ J. When the metal surface is illuminated by the light of wavelength 6400 Å, then the maximum kinetic energy of emitted photo-electrons will be (Planck’s constant $ h=6.4\times {{10}^{-34}}Js $ ) [MP PMT 1989]
Options:
A) $ 14\times {{10}^{-19}}\ J $
B) $ 2.8\times {{10}^{-19}}\ J $
C) $ 1.4\times {{10}^{-19}}J $
D) $ 1.4\times {{10}^{-19}},eV $
Show Answer
Answer:
Correct Answer: C
Solution:
$ {K_{\max }}=\frac{hc}{\lambda }-W_{0}=\frac{6.4\times {{10}^{-34}}\times 3\times 10^{8}}{6400\times {{10}^{-10}}}-1.6\times {{10}^{-19}} $ $ =1.4\times {{10}^{-19}},J $
BETA
