$A$ hydrogen atom absorbs radiation of wavelength $975 \, \text{\AA}$ to transition from the ground state to an excited state. To which energy level will the atom transition?

$A$ sample of hydrogen atoms is in an excited state (all the atoms). The photons emitted from this sample are made to pass through a filter through which light having a wavelength greater than $800 \ nm$ can only pass. Only one type of photon is found to pass through the filter. The sample's initial excited state is: [Take $hc = 1240 \ eV \cdot nm$,ground state energy of hydrogen atom = $-13.6 \ eV$.]

Energy of $H$-atom in the ground state is $-13.6 \; eV$. The energy needed to ionize a hydrogen atom which is in its second excited state is ....... $eV$.

When an electron transition takes place from an excited state to the ground state in a hydrogen atom, then:

$A$ difference of $5.4 \ eV$ separates two energy levels in an atom. What is the frequency of radiation emitted when the atom makes a transition from the upper level to the lower level? (Take $1 \ eV = 1.6 \times 10^{-19} \ J$,$h = 6.625 \times 10^{-34} \ Js$)

The figure indicates the energy level diagram of an atom and the origin of six spectral lines in emission (e.g.,line no. $5$ arises from the transition from level $B$ to $A$). Which of the following spectral lines will also occur in the absorption spectrum?