The ratio of the radius of the third orbit to that of the second orbit in a hydrogen atom is
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 9 : 4
For hydrogen atom, the radius of nth orbit is given by:
$r_n = n^2 a_0$
Hence, the ratio of the radius of the third orbit to that of the second orbit is:
$\frac{r_3}{r_2} = \frac{3^2 a_0}{2^2 a_0} = \frac{9}{4}$
∴ The required ratio is $\frac{9}{4}$ or 9 : 4