The wavelength of a spectral line for an electronic transition is inversely related to:

Options

A. Number of electrons undergoing transition
B. Nuclear mass of an atom
C. The difference of energy levels involved in transition
D. The velocity of the electron undergoing transition

Answer

C

Explanation

Smaller the energy difference between orbits lesser the energy released when the electron falls from a higher to lower orbit.
Lesser the energy higher the wavelength as per Planck’s Law `E = (hc)/(lamda) or E prop (1)/(lamda)`