Question

The work function of a metal is 0.1 eV. Calculate the threshold frequency for photo-electric emission.

Answer 1

${\varphi }_0=0.1eV=0.1\times 1.6\times {10}^{-19}$ Joule
$h=6.6\times {10}^{-34}$ Joule-sec.
${\varphi }_0=h{v}_0$
$v_0=\frac{{\varphi }_0}{h}=\frac{0.1\times 1.6\times {10}^{-19}}{6.6\times {10}^{-34}}$
$v_0=0.029\times {10}^{15}$Hz.