Question

The Bohr radius for the hydrogen atom ($n=1$) is approx $0.53A^o$. The radius for the first excited state ($n=2$ orbit) is (in $A^o$):

• A. $0.13$
• B. $1.06$
• C. $4.77$
• D. $2.12$

Answer 1

The correct option is D $2.12$

According to the Bohr atomic model for the same atom, $r_n\propto n^2$.

Therefore, $\frac{r_2}{r_1}=\frac{2^2}{1^2}=4$

$r_2=4\times r_1=4\times 0.53A^o=2.12A^o$