Atomic Structure

The work functions (in eV ) of $\mathrm{Mg}, \mathrm{Cu}, \mathrm{Ag}, \mathrm{Na}$ respectively are $3.7,4.8,4.3,2.3$. From how many metals, the electrons will be ejected if their surfaces are irradiated with an electromagnetic radiation of wavelength 300 nm ?

$\left(h=6.6 \times 10^{-34} \mathrm{Js}, 1 \mathrm{eV}=1.6 \times 10^{-19} \mathrm{~J}\right)$