Question

Velocity of electron in $3^{rd}$ shell of $L{i}^{+2}$ is:

($c\to$ velocity of light)

• A. $\frac{1}{137}c$
• B. $\frac{1}{274}c$
• C. $\frac{2}{137}c$
• D. $\frac{1}{3\times 137}c$

Answer 1

The correct option is A $\frac{1}{137}c$

$\frac{1}{137}C$

because radius of orbit $r_n=\frac{n^2}{z}\times 0.529\times {10}^{-8}cm$

When $n=3,z=3$

$r_3=1.587$

in terms of $C$ velocity of electron can be written as $\frac{1}{137}C$