The ratio of the energy of a photon of $2000 \ \mathring{A}$ wavelength radiation to that of $4000 \ \mathring{A}$ radiation is

$A$ certain atomic transition from an excited state to the ground state of the hydrogen atom in one or more steps gives rise to four lines in the ultraviolet region of the spectrum. How many lines does this transition produce in the infrared region of the spectrum?

If the series limit of wavelength of the Lyman series for the hydrogen atom is $912 \ \mathring{A}$,then the series limit of wavelength for the Balmer series of radiation which may be emitted is :

Find the frequency and wavelength of light required for the ionization of the solution. (Ionization energy of the solution $= 8.2 \times 10^{-19} \ J$)

The energy of an electron in the $n^{th}$ orbit of a hydrogen atom is given by:

The element used by Rutherford in his famous scattering experiment was