Recap_Template

Module 5 : MODERN PHYSICS

Lecture 23 : Particle and Waves

Recap
In this lecture you have learnt the following
	Traditional picture of light being a wave cannot explain several phenomena such as blackbody radiation and
	photoelectric effect.
	A blackbody is a an object whic absorbs all the radiation that falls on it.
	A blackbody is also a perfect emitter, i.e. it emits all the radiation that it absorbs.
	Intensity of radiation emitted by a blackbody is proportional to the fourth power of its temperature (Stefan's law).
	The wavelength at which the emitted radiation has the maximum intensity is inversely proportional to its temperature
	(Wien's law).
	Classical Rayleigh-Jeans' formula leads to the ultraviolet catastrophe at short wavelength.
	Planck proposed that oscillating atoms emit or absorb radiation in quanta. Using Boltzmann distribution, he derived
	a formula for radiation which satisfactorily explains the blackbody radiation spectrum.
	Congratulations! you have finished Lecture-23. To view the next Lecture select it from the left hand side of the page.