In the Bohr model of the hydrogen atom,the lowest orbit corresponds to:

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 diagram shows the lowest four energy levels for an electron in a hypothetical atom. The electron is excited to the $-1\, eV$ level and transitions to the lowest energy state by emitting exactly two photons. Which of the following energies could not belong to either of the photons (in $, eV$)?

As an electron makes a transition from an excited state to the ground state of a hydrogen-like atom/ion:

$A$ 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 total energy of an electron in an orbit of a hydrogen atom is $E$. The potential energy of the electron in the same orbit is: