An electron of a hydrogen atom in an excited state has an energy $E_n = -0.85 \ eV$. The maximum number of allowed transitions to lower energy levels is:

According to the Bohr atom model,in which of the following transitions will the frequency be maximum?

When a hydrogen atom is raised from the ground state to the excited state,

In an atom, the difference between two energy levels is $3.31 \ eV$. The wavelength of the radiation emitted when the transition takes place between these levels is nearly: (in $Å$)

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

$A$ hydrogen atom (ionisation potential $13.6 \ eV$) makes a transition from the third excited state to the first excited state. The energy of the photon emitted in the process is.......$eV$.