Core Atomic
Structure: Nature of light
Slide 14 of 24
Max Planck’s
Quantum Hypothesis
If an oscillator could radiate only by a
discrete act in which its energy changed from nhn to (n - 1)hn, then was it not reasonable that light itself
was composed of discrete
entities of energy hn?
Planck’s hypothesis was able
thus to explain the radiation from heated solids.
Not only that, this idea found application and
support in Einstein’s explanation of the photoelectric effect.
In the large-scale world of people, cars, golf
balls, and the like, changes in energy appear to be smooth because the amount of energy tied up
in a unit of energy such as hn is amazingly small—too small for us to
observe.
–Note how small the value of Planck’s constant is.
Einstein proposed (in 1905) that the
photoelectric effect could be explained if light itself consisted of discrete particles or
photon of energy (a packet of energy) hn.