The kinetic energy of the electron in an orbit of radius `r` in hydrogen atom is (`e =` electronic charge)

Options

A. `(e^(2))/(r )`
B. `(e^(2))/(2r)`
C. `(e^(2))/(r^(2))`
D. `(e^(2))/(2r^(2))`

Answer

b

Explanation

`(mv_(n)^(2))/(r_(n))=(1)/(4pi epsilon_(0)).((ze^(2))/(r_(n)^(2)))=(kze^(2))/(r_(n)^(2))`
`mv^(2) x=(Ze^(2))/(r_(v))`
Kinetic energy of electron in `nth` orbit
`KE=(1)/(2)mv_(n)^(2)=(kZe^(2))/(2r_(n))`
or
`KE=(e^(2))/(2r)`