Q. The velocity of an electron placed in 3rd orbit of H atom, will be
A) $2.79 \times 10^{7}\ cm/s$
B) $9.27 \times 10^{27}\ cm/s$
C) $7.29 \times 10^{7}\ cm/s$
D) $92.7 \times 10^{7}\ cm/s$
Explanation
(c)
$v = \frac{2.18 \times 10^{8} \times Z}{n}\ cm\ s^{- 1}$
For H atom, $Z = 1$ and third orbit, $n = 3,$
$v_{3} = \frac{2.18 \times 10^{8} \times 1}{3}$
$= 7.26 \times 10^{7}\ cm\ s^{- 1}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.