The total energy of a hydrogen atom in its ground state is $-13.6 \ eV$. If the potential energy in the first excited state is taken as zero,then the total energy in the ground state will be ..... $eV$.

Which of the following phenomena suggests the presence of electron energy levels in atoms?

Energy levels $A, B, C$ of a certain atom correspond to increasing values of energy,that is,$E_A < E_B < E_C$. If $\lambda_1, \lambda_2, \lambda_3$ are the wavelengths of radiations corresponding to the transitions $C$ to $B$,$B$ to $A$,and $C$ to $A$ respectively,as shown in the figure. Which of the following statements is correct?

$A$ hydrogen atom falls from $n^{\text{th}}$ higher energy orbit to the first energy orbit $(n=1)$. The energy released is equal to $12.75 \text{ eV}$. The $n^{\text{th}}$ orbit is:

In a hydrogen atom,the electron makes a transition from the $(n+1)^{\text{th}}$ level to the $n^{\text{th}}$ level. If $n >> 1$,the frequency of the radiation emitted is proportional to:

The ratio of energies of photons produced due to the transition of an electron in a hydrogen atom from its $(a)$ second to first energy level and $(b)$ highest energy level to the second level is: