The kinetic energy of the electron in an orbit of radius r i... | PHYSICS - THE LINE SPECTRA OF THE HYDROGEN ATOM | SolveeIt | Solveeit

Today, August 19

Question

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

A

$\frac{e^{2}}{r^{2}}$

B

$\frac{e^{2}}{2r}$

C

$\frac{e^{2}}{r}$

D

$\frac{e^{2}}{2r^{2}}$

Answer

$\frac{e^{2}}{2r}$

Explanation

Solution

Potential energy of electron in n^th orbit of radius r in H-atom $U = - \frac{e^{2}}{r}$ (in CGS)

∵ K.E. $= \frac{1}{2}|P.E.|$ ⇒ $K = \frac{e^{2}}{2r}$