Q. The work function of a substance is 4.0 eV. The longest wavelength of light that can cause photoelectron emission from this substance is approximately
A) 540 nm
B) 400 nm
C) 310 nm
D) 220 nm
Explanation
(c) ${\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \lambda}_{0} = \frac{hc}{W_{0}} = \frac{12400}{4}$
= $3100\mathring{\mathrm{A}} = \ 310\ nm$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.