Question

The work function (Φ) for a metal is 6.10×10-19 J. What is the longest wavelength of electromagnetic radiation that can eject an electron from the surface of a piece of the metal? Answer in nm.

Answer 1

Answer: 326 nm

Solution:

$E=\frac{hc}{\lambda}$

$\lambda=\frac{hc}E$

$\lambda=\frac{6.626×10^{-34}Js\;×\;3×10^8 m/s}{6.10×10^{-19}J}=3.26×10^{-6}m=326\,nm$