Q. What is the work function (in eV) of a substance if photoelectrons are just ejected for a monochromatic light of wavelength $\lambda = 3300\mathring{\mathrm{A}}$?
A) 3.75
B) 3.25
C) 1.63
D) 0.75
Explanation
(a) Work function , $\phi = \frac{hc}{\lambda}$
= $\frac{6.6 \times 10^{- 34} \times 3 \times 10^{8}}{3300 \times 10^{- 10}} = 6.0 \times 10^{- 19}$J
=$\frac{6.0 \times 10^{- 19}}{1.6 \times 10^{- 19}}\ eV = 3.75\ eV$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.