If the angular momentum of an electron in an orbit is J then the K.E. of the electron in that orbit is

Options

A. `J^(2)/(2mr^(2))`
B. `(Jv)/r`
C. `J^(2)/(2m)`
D. `J^(2)/(2pi)`

Answer

A

Explanation

Angular momentum `=mrv=J`
`:. v=J/(mr)`
K.E. of electron `=1/2 mv^(2)=1/2 m(J/(mr))^(2)`
`=J^(2)/(2mr^(2))`