The work function for a certain metal is 4.2 eV. Will this metal give photoelectric emission for incident radiation of wavelength 330 nm?
No
Work function of the metal, $\phi_{0}=4.2 \mathrm{eV}$
Charge on an electron, e = 1.6 × 10−19 C
Planck’s constant, h = 6.626 × 10−34 Js
Wavelength of the incident radiation, λ = 330 nm = 330 × 10−9 m
Speed of light, c = 3 × 108 m/s
The energy of the incident photon is given as:
$E=\frac{h c}{\lambda}$
$=\frac{6.626 \times 10^{-34} \times 3 \times 10^{8}}{330 \times 10^{-9}}=6.0 \times 10^{-19} \mathrm{~J}$
$=\frac{6.0 \times 10^{-19}}{1.6 \times 10^{-19}}=3.76 \mathrm{eV}$
It can be observed that the energy of the incident radiation is less than the work function of the metal. Hence, no photoelectric emission will take place.