The threshold frequency `v_(0)` for a metal is `7xx10^(14)s^(-1)` . Calculate the kinetic energy of an electron emitted when radiation of frequency `v = 1.0 xx 10^(15)s^(-1)` hits the metal .

Explanation

According to Einstein's equation
Kinetic energy = `1//2m_(e)v^(2) = h( v-v_(0))`
= `( 6.626xx10^(-34)J s)( 1.0xx10^(15)s^(-1)-7.0xx10^(14)s^(-1))`
= `(6.626 xx 10^(-34)Js) ( 10.0xx 10^(14)s^(-1)- 7.0xx10^(14)s^(-1))`
= `(6.626xx 10^(-34) Js)xx(3.0xx10^(14)s^(-1))`
= `1.988xx10^(-19)J`