A light source of wavelength `lambda ` illuminates a metal and ejects photo-electrons with `(K.E.)_("max") = 4 eV` . Find the value of work function ?

Options

A. 1eV
B. 2eV
C. 0.5 eV
D. None of these

Answer

D

Explanation

Work function `phi= h upsilon_0`
`phi ` for each metal is constant .
if incident energy is known then `phi` can be calculated.