Question

The radius of electron's second stationary orbit in Bohr's atom is R. The radius of the third orbit will be

• A. $3R$
• B. $2.25R$
• C. $9R$
• D. $\frac{R}{3}$

Answer 1

The correct option is B $2.25R$

$r\alpha n^2\Rightarrow \frac{r_{\left(2\right)}}{r_{\left(3\right)}}=\frac{4}{9}\Rightarrow r_{\left(3\right)}=\frac{9}{4}R=2.25R$