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

Answer

A

Explanation

Angular momentum `= mrv = J " " therefore v= (J )/( mr)`
K.e of electron `=1/2 mv^2 = 1/2 m ((j )/(mr))^2 = (j^2 )/(2 mr^2)`