The threshold frequency `V_(0) ` for a metal is `7.0 xx 10^(14) s^(-1)` Calculation the kinetic energy of and electron emitted when radiation of frequency `v=1.0 xx 10^(15) s^(-1)` hits the metal .

Explanation

According to Einstein equation
Kinetic energy `=(1)/(2) m_(e ) v^(2)`
where `v_(0) = 7.0 xx 10^(14) s^(-1)`
`=(6.626 xx 10^(34) j s ) ( 1.0 xx 10^(15) -7.0 xx 10^(14) ) s^(-1)`
`=6.626 xx 10^(34) (10 xx 10^(14) -7.0 xx 10^(14))`
`19.878 xx 10^(-20)`
`=1.9879 xx 10^(19)J`