Up to what potential V can a zinc ball (work function 3.74 eV) removed from other bodies be charged by irradiating it with light of `lamda=200 nm`?

Options

A. 2.5 V
B. 1.8 V
C. 2.2 V
D. 3 V

Answer

A

Explanation

When the positive potential of the ball is enough to hold back the most energetic photoelctron, the ball will not emit photoelectrons.
`(hc)/(lamda)-phi=Ve`
`V=((hc)/(lamda)-phi)/(e)`
`=(6.63xx10^(-34)xx3xx10^(8))/(200xx10^(-9)xx1.6xx10^(-19))-3.74`
`=6.216-3.74=2.5 V`