A metal surface has a work function $\varphi =2.0\text{eV}$. Light of wavelength $500\text{nm}$ shines on it. What is the maximum kinetic energy of the emitted electrons?

Step-by-step solution

1. Photon energy is $E_{\gamma }=\frac{hc}{\lambda }$ with $hc=1240\text{eVnm}$.
2. Thus $E_{\gamma }=\frac{1240}{500}=2.48\text{eV}$.
3. Maximum kinetic energy $K_{\max }=E_{\gamma }-\varphi$.
4. Substituting, $K_{\max }=2.48-2.0=0.48\text{eV}$.

Concept tested: Photoelectric effect – kinetic energy calculation

Published 11 September 2026 · How this solution was prepared and checked