Q. The photoelectric threshold wavelength for potassium (work function being $2\ eV$) is
A) $310\ nm$
B) $620\ nm$
C) $1200\ nm$
D) $2100\ nm$
Explanation
(b) $\lambda_{0} = \frac{12375}{W_{0(eV)}} = \frac{12375}{2} = 6187.5\mathring{\mathrm{A}} \simeq 620\ nm$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.