Q. A metal surface of work function 1.07 $eV$ is irradiated with light of wavelength 332 nm. The retarding potential required to stop the escape of photoelectrons is
A) 1.07 eV
B) 2.66 eV
C) 3.7 eV
D) 4.81 eV
Explanation
(b) Retarding potential,
$V_{s} = \frac{hc}{\lambda e} - \frac{\phi_{0}}{e} = \frac{1240 \times 10^{- 9}}{330 \times 10^{- 9}} - 1.07$
$= 3.73 - 1.07 = 2.66\ V$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.