Question

The minimum energy required for the emission of a metal electron is $13.24\times {10}^{-19}J$.calculate the critical frequency and the corresponding wavelength of the photon(threshold wavelength) required to eject the electron?

Answer 1

$E=hv$

$v=13.24\times {10}^{-19}/6.626\times 10-34$

$=2\times {10}^{15}{s}^{-1}$

and $v\lambda =c$ and $\lambda =c/v$

$\lambda =3\times {10}^8/2\times {10}^{15}=1.5\times {10}^{-7}m$