7  PARTICLE NATURE OF LIGHT: THE PHOTON
Photoelectric effect thus gave evidence to the strange fact that light in
interaction with matter behaved as if it was made of quanta or packets of
energy, each of energy h n Is the light quantum of energy to be associated with a particle Einstein
arrived at the important result, that the light quantum can also be
associated with momentum (h n/c) A definite value of energy as well as
momentum is a strong sign that the light quantum can be associated
with a particle