1. Black body radiation and ultraviolet catastrophe
an object which absorbs all radiation incident upon it and re-radiates energy which is not dependent upon the type of radiation which is incident upon it. The radiated energy is considered to be produced by standing wave of the cavity which is radiating.

2. Black body radiation

3. Experimental Curves

4. At high values of wavelength the wave model (Rayleigh Jeans plot) does not predict the curve properly

5. Max Planck’s solution
Planck suggested that instead of the absorption of radiation by a black body being continuous (all frequency values), only certain frequencies or wavelengths were absorbed and that…………..
E=absorbed energy = h f
His curve agreed with the observations
The radiation is quantised