The ground state energy of a hydrogen atom is $-13.6 \ eV$. The potential energy of the electron in the first excited state of hydrogen is (in $eV$)

The minimum energy required to excite a hydrogen atom from its ground state is.....$ eV$.

The first excited state of a hydrogen atom is $10.2 \, eV$ above its ground state. The temperature needed to excite hydrogen atoms to the first excited level 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 ratio of energies of photons produced due to the transition of an electron in a hydrogen atom from its $(i)$ $3^{\text{rd}}$ to $2^{\text{nd}}$ energy level and (ii) highest energy level to $3^{\text{rd}}$ level is:

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