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 .......

The radius of orbit of an electron and the speed of an electron in the ground state of a hydrogen atom are $5.5 \times 10^{-11} \,m$ and $4 \times 10^6 \,m/s$ respectively. Then,the orbital period of this electron in the first excited state will be

The radius of the first orbit of a hydrogen atom is $0.5 \, \mathring{A}$ and the speed of the electron is $2.2 \times 10^6 \, m/s$. Find the magnetic induction at the proton due to the motion of the electron in $Tesla$.

The angular momentum of an electron in the $2^{nd}$ excited state of a Helium ion $(He^+)$ is

The magnitude of angular momentum,orbit radius,and frequency of revolution of an electron in a hydrogen atom corresponding to quantum number $n$ are $L, r$,and $f$ respectively. According to Bohr's theory of the hydrogen atom,which of the following is constant for all orbits?

The ground state energy of a hydrogen atom is $-13.6 \text{ eV}$. The potential energy of the electron in this state is: (in $\text{ eV}$)