Question

The ratio of the velocity of light and the velocity of electron in the first orbit of a hydrogen atom.
`[Given h = 6.624 xx 10^-27 erg-sec , m = 9.108 xx 10^-28 g, r = 0.529 xx 10^-8 cm]`.
A. 137
B. `(1)/(137)`
C. `(1)/(13700)`
D. 13700

Answer 1

Correct Answer - A
(a) `v = (h)/(2 pi m)`
=`(6.624 xx 10^-27)/(2 xx 3.14 xx 9.108 xx 10^-28 xx 0.529 xx 10^-8)`
=`2.189 xx 10^8 cm//sec`
`(c)/(v) = (3 xx 10^10)/(2.189 xx 10^8) = 137`.