Work function of aluminium plate is `phi` when radiation of hf energy is incident on metal surface photoelectron of kinetic energy K is emitted .Now if frequency of radiation is made double,kinetic energy of photoelectron will become…..

Options

A. 2K
B. K
C. K=hf
D. `K+E_(0)`

Answer

C

Explanation

By using Eintein.s equation for photo electricity
`hf=phi+(1)/(2)mv^(2),hfphi+K`
`therefore phi=hf-K` …(1)
Now ,if radiation of 2f frequency is incident let kinetic energy become K.
then h.2f=`phi`+K.…..(2)
`therefore` 2hf=hf-K+K.
[Putting value of equation (1) in equation (2)]`therefore` K.+hf+K