Q. The work function for metals $A,\ B$ and $C$ are respectively $1.92\ eV,\ 2.0\ eV$ and $5\ eV.$ According to Einstein’s equation, the metals which will emit photo electrons for a radiation of wavelength $4100\ \mathring{\mathrm{A}}$ is/are
A) None of these
B) $A$ only
C) $A$ and $B$ only
D) All the three metals
Explanation
(c) Momentum $p = \frac{E}{c} \Rightarrow E^{2} = p^{2}c^{2}$
$= \frac{12375}{4100} = 3.01\ eV$
Work functions of metal $A$ and $B$ are less than $3.01eV,$ so $A$ and $B$ will emit photo electrons
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.