Light of wavelength 400 nm is incident continuously on a cesium ball (work function 1.9 eV) The maximum potential to which the ball will be charged is-

3.1 V 1. 2 V Zero Infinite

1. 2 V

$eV_s=\frac{12400}{4000}-1.9=3.1-1.9$ $eV_s=1.2eV$ $V_s=1.2V$