The velocity of an electron in the first Bohr orbit of $He^+$ ion is .......

The time period of revolution of an electron in its ground state orbit in a hydrogen atom is $1.6 \times 10^{-16} \; s$. The frequency of revolution of the electron in its first excited state (in $s^{-1}$) is:

The kinetic energy of the electron in an orbit of radius $r$ in a hydrogen atom is proportional to ($e$ = electronic charge).

Which of the following is quantized according to Bohr's theory of the hydrogen atom?

In the Bohr model,an electron moves in a circular orbit around the nucleus. Considering an orbiting electron to be a circular current loop,the magnetic moment of the hydrogen atom,when the electron is in the $n^{th}$ excited state,is ($e=$ electronic charge,$m_{e}=$ mass of the electron,$h=$ Planck's constant).

According to de Broglie,if the wavelength of an electron in the second orbit is $10^{-9} \ m$,then the circumference of the orbit is .......