The maximum kinetic energy of the photoelectrons is formed to be `6.63 xx 10^(-19) J`, when the metal is irradiated with a radiation of requency `2 xx 10^(15) Hz`. The threshold frequency, of the metal is about?

Options

A. `1xx10^(15) s^(-1)`
B. `2xx10^(19) s^(-1)`
C. `3xx10^(15) s^(-1)`
D. `1.5xx10^(15) s^(-1)`

Answer

A

Explanation

`KE =h (v-v_(0))`
`v_(0)=v -(KE)/(h) =2xx10^(15) -(6.63xx10^(-19))/(6.63xx10^(-34)) =1xx10^(15)s^(-1)`