The work function of the nickel is $5 \;eV$. When a light of wavelength 2000 A falls on it, it emits photo electrons in the circuit. Then the potential difference necessary to stop the fastest electrons emitted is (given $h= 6.67 \times 10^{-34}\;J-s$)

Question

$$\begin {array} {1 1} (a)\;1.0\; V & \quad (b)\;1.75\;V \\ (c)\;1.25\;V & \quad (d)\;0.75\;V \end {array}$$