question_answer

A source of light is placed at a distance of 1 m from a photocell and the cut-off potential is found to be V0. If the lamp is now placed at a distance of 2 m, the cut-off potential will become :

A) \[2{{V}_{0}}\]                                   

B) \[\frac{{{V}_{0}}}{2}\]

C) \[\frac{{{V}_{0}}}{4}\]                                   

D)  \[{{V}_{0}}\]