Answer & explanation
Correct answer: option 3
$ \lambda = \frac{2\pi}{k}= 5 \times 10^{-7} m = 5000A^o$
$ \text{Stopping Potential } V_s = \frac{hc}{e\lambda} - \frac{\phi}{e} = \frac{12375}{5000}V - 2V = 0.48V$
Correct answer: option 3
$ \lambda = \frac{2\pi}{k}= 5 \times 10^{-7} m = 5000A^o$
$ \text{Stopping Potential } V_s = \frac{hc}{e\lambda} - \frac{\phi}{e} = \frac{12375}{5000}V - 2V = 0.48V$