Electrons ejected from the surface oa a metal ,when light of certain frequency is incident on it ,are stoppeed fully by a retarding potenital of 3V. Photoelectric effect in this metallic surface begins at a frequency `6xx10^(14)s^(-1)`.The frequency of the incident light in `s^(-1)` is [Planck's constant `=6.4xx10^(-34)`Js, charge on the electron `=1.6xx10^(-19)C]`

Options

A. `7.5xx10^(13)`
B. `13.5xx10^(13)`
C. `13.5xx10^(14)`
D. `7.5xx10^(13)`

Answer

C

Explanation

The expression for frequency of the incident light given as ,`hv=hv_(o)+phi`
`hv_(o)+evimplies v=v_(o)+(eVo)/(h)`
`=(6xx10^(14))+((1.6xx10^(-19))(3))/((6.4xx10^(-34))=(6xx10^(14))+(7.5xx10^(14))`
`v=13.5xx10^(14)s^(-1)`