As the combustible materials burn, some of the chemical energy is transformed into heat energy, and some are transformed into light energy. Light energy, also known as radiation or electromagnetic energy, is a type of kinetic energy that takes the form of visible light waves, such as the light from a match.
Answer:
by moving between defined energy levels
Saturated hydrocarbons consists of C-C single bond whereas Unsaturated hydrocarbons consists C-C double/triple bond.