Q. In the Bohr model of hydrogen atom, the electron is pictured to rotate in a circular orbit of radius $5\ \times \ 10^{- 11}$ m, at a speed $2.2\ \ \times \ 10^{6}\ ms^{- 1}$. What is the current associated with electron motion?
A) 1.12 mA
B) 3 mA
C) 0.75 mA
D) 2.25 mA
Explanation
(a) Frequency of revolution of electron,
$\ \ \ \ \ \ \ f\ = \frac{v}{2\pi r}$ =$\frac{2.2\ \times \ 10^{6}}{2\pi(5\ \times \ 10^{- 11})}$ = 7.0 $\times$ $10^{15}\ $Hz
Current associated$,\ i$=$q$ $f$
= $(1.6\ \times \ 10^{- 19})(7.0\ \times \ 10^{15})$
$= 11.2\ \times \ 10^{- 4}\ A\ = \ 1.12\ mA$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.