It explains both wave & particle theories of light. It also includes Maxwell's mathematical equations and postulates of Planck quantum theory.

1. (Maxwell’s equations)
A body can absorb and emit
discontinuously tiny packets of
energy known as quantum.
Energy-frequency relationship
Light emits whole number
multiples of quantum.
The amount of energy less
than a quantum is neither
emitted nor absorbed.
(Postulates of Planck theory)
De-Broglie explained dual
nature of light based on these
two theories.
Classical physics Quantum physics