In figure, E1 to E6 represent some of the energy levels of an electron in the hydrogen atom.Which one of the following transitions produces a photon of wavelength in the ultraviolet region of the electromagnetic spectrum?

The wavelengths of the hydrogen spectrum could be arranged in a formula or series named after its discoverer. For ultraviolet spectrum the series is called Lyman series, for visible spectrum the Blamer series, and for infrared region we have the Paschen series. The ultraviolet series is obtained when the energy of the atom falls from higher states to the energy level corresponding to n=1 . Thus, ultraviolet radiation can only be possible with transition from E2 to E1 out of the given transitions.