$A$ hydrogen atom in its ground state is irradiated by light of wavelength $970 \mathring A$. Taking $hc/e = 1.237 \times 10^{-6} \text{ eV m}$ and the ground state energy of the hydrogen atom as $-13.6 \text{ eV}$,the number of lines present in the emission spectrum is

The maximum wavelength of incident radiation required to ionize a hydrogen atom in its ground state is nearly

What is the energy of the electron revolving in the third orbit expressed in $ eV $ (in $eV$)?

Energy of an electron in the second orbit of a hydrogen atom is $E$. The energy of an electron $E_3$ in the third orbit of a helium $(He^+)$ ion will be:

$A$ hydrogen atom emits blue light when it changes from the $n = 4$ energy level to the $n = 2$ level. Which colour of light would the atom emit when it changes from the $n = 5$ level to the $n = 2$ level?

The energy levels of a certain atom are $A, B,$ and $C$ in increasing order of energy,i.e.,$E_A < E_B < E_C$. If $\lambda_1, \lambda_2,$ and $\lambda_3$ are the wavelengths of radiation corresponding to transitions from $C$ to $B$,$B$ to $A$,and $C$ to $A$ respectively,which of the following relations is correct?