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

Explanation

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