Let $T_{1}$ and $T_{2}$ be the energy of an electron in the first and second excited states of a hydrogen atom,respectively. According to the Bohr's model of an atom,the ratio $T_{1}: T_{2}$ is

The energy of an electron in the fourth excited state of the hydrogen atom is

An electron in a hydrogen atom first jumps from the third excited state to the second excited state and then from the second excited state to the first excited state. The ratio of the wavelengths $\lambda_1 : \lambda_2$ emitted in the two cases is

The ground state energy of the hydrogen atom is $-13.6 \ eV$. The kinetic and potential energy of the electron in the second excited state are,respectively:

The ratio of energies of photons produced due to the transition of an electron of a hydrogen atom from its $(i)$ second to first energy level and $(ii)$ highest energy level to $2^{nd}$ level is respectively: (in $: 1$)

The ratio of the kinetic energies of the electrons in the third and fourth excited states of the hydrogen atom is