Q. Radiations of two photon’s energy, twice and ten times the work function of metal are incident on the metal surface successively. The ratio of maximum velocities of photoelectrons emitted in two cases is
A) 1 : 2
B) 1 : 3
C) 1 : 4
D) 1 : 1
Explanation
(b) $\frac{1}{2}mv_{1}^{2} = 2\phi_{0} - \phi_{0} = \phi_{0}$ and $\frac{1}{2}mv_{2}^{2} = 10\phi_{0} - \phi_{0} = 9\phi_{0}$
$\therefore\ \frac{v_{1}}{v_{2}} = \sqrt{\frac{\phi_{0}}{9\phi_{0}}} = \frac{1}{3}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.