The work function of a certain metal is $3.31 \times 10^{-19}\;J$. Then the maximum kinetic energy of photo electrons emitted by radiation of wavelength 5000 A is : (given $h=6.62 \times 10^{-34}\;J-s, C= 3 \times 10^{8}ms^{-1},e= 1.6 \times 10^{-19}$ coul.)

Question

\[\begin {array} {1 1} (1)\;2.48\;eV & \quad (2)\;0.41 e\;V \\ (3)\;2.07\;eV & \quad (4)\;0.82\;eV \end {array}\]