Question

Molecular vibrational energy transitions are observed in the infrared, molecular rotational transitions in the microwave and electronic transitions in the ultraviolet-visible range. Which transitions require the most energy and which the least energy

Answer 1

Solution :-

The wavelength of the radiations increases in the order as follows

Ultra violet < infrared < microwave

The wavelength and energy of the electromagnetic radiation are inversely proportional therefore as the wavelength increases then energy decreases

That means microwave has the lowest energy and ultra violet have higher energy

Hence the electronic transitions requires highest energy and molecular rotational transitions require lowest energy. Molecular Vibrational transitions require intermediate energy between the ultraviolet and microwave radiations.

Highest (most) energy = electronic transitions

Lowest (least) energy = molecular rotational transitions.