In Bohr's model,the atomic radius of the first orbit is $r_0$,then the radius of the third orbit is

Magnetic field at the centre of the hydrogen atom due to the motion of an electron in the $n^{\text{th}}$ orbit is proportional to:

The angular momentum of the orbital electron is an integral multiple of:

Which of the following statements about the Bohr model of the hydrogen atom is false?

Kinetic energy of the electron in a hydrogen atom is $\frac{e^{2}}{8 \pi \varepsilon_{0} r}$. Then its potential energy is . . . . . . .

The de-Broglie wavelength of an electron moving in the $n^{\text{th}}$ Bohr orbit of radius $r$ is