Question

If the radius of second stationary orbit (in Bohr's atom) is R. Then, the radius of third orbit will be:

• A. R/3
• B. 9R
• C. R/9
• D. 2.25R

Answer 1

The correct option is D 2.25R

$r=0.529\times \frac{n^2}{z}$

$r\propto n^2$

$R\propto (2{)}^2$ $.......\left(1\right)$

$R_1\propto (3{)}^2$ $.......\left(2\right)$

Divide (1) by (2)

$\frac{R_1}{R}=\frac{4}{9}$

$R_1=\frac{9R}{4}$

$R_1=2.25R$