Question

In Bohr's model of the hydrogen atom the ratio between the period of revolution of an electron in the orbit of $n=1$ to the period of the revolution of the electron in the orbit $n=3$ is:

• A. $1:2$
• B. $2:1$
• C. $1:4$
• D. $1:27$

Answer 1

The correct option is D $1:27$

We know that, $T_n\propto \frac{n^3}{Z^2}$ (Z = 1 for H)

Hence, $T_n\propto n^3$

$\therefore \frac{T_1}{T_2}=\frac{1^3}{3^2}=\frac{1}{27}$