Question

The velocity of electron in the first Bohr orbit of $H{e}^{+}$ ion is-

• A. c
• B. c/137
• C. 2c/137
• D. 4c/137

Answer 1

The correct option is D 4c/137

For$H{e}^{+}$ ion, $Z=2andn=1$

$V=\frac{1}{2{\epsilon }_o}\frac{Z{e}^2}{nh}=\frac{Z}{n}\times 2.18\times {10}^6=8.73\times {10}^6=\frac{4c}{137}m{s^{-}}^1$

Hence, velocity of electron is $\frac{4c}{137}m{s}^{-1}$