Question

Ratio of radius of first orbit of $H{e}^{+}$ to the second orbit of hydrogen atom will be

• A. $1:1$
• B. $1:2$
• C. $1:8$
• D. $1:4$

Answer 1

The correct option is C $1:8$

Answer (4)
$r_n\propto \frac{n^2}{Z}$
$\frac{r_{H{e}^{+}}}{r_H}=\frac{1}{2}\times \frac{1}{(2{)}^2}=\frac{1}{8}$
$r_{H{e}^{+}}:r_H=1:8$