Question

Which of the following statements are true regarding Bohr's model of hydrogen atom?
A. Orbiting speed of electron decreases as it shifts to discrete orbits away from the nucleus
B. Radii of allowed orbits of electron are proportional to the square of principal quantum number
C. Frequency with which electrons orbits around the nucleus in discrete orbits is inversely proportional to the cube of principal quantum number
D. Binding force with which the electron is bound to the nucleus increases as it shifts to outer orbits

• A. $A$ and $C$
• B. $B$ and $D$
• C. $A, B$ and $C$
• D. $B, C$ and $D$

Answer 1

Answer: (A)

Electron after absorbing $10.2 eV$ energy goes to its first excited state $( n =2)$ from the ground state $( n =1)$
$\therefore $ Increase in momentum $v \propto \frac{1}{n}$
$v \propto \frac{1}{n^{3}}$
$ \Rightarrow r \propto n^{2}$