Q. 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) $\frac{e^{2}}{2r^{2}}$
Explanation
(b) Potential energy of electron in $n^{th}$ orbit of radius $r$ in $H$-atom $U = - \frac{e^{2}}{r}$ (in CGS)
$\because\ K.E.\ = \frac{1}{2}|P.E.| \Rightarrow K = \frac{e^{2}}{2r}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.