.1 a) What is black body and black body radiation? Write down the Plank’s Postulates and derive Plank’s energy density formula? Show that the Plank’s energy density is

formula valid for all types of wave length.

b) The effective surface temperature of the Sun is 5800K at what wave length

would you expect the Sun to radiate most strongly? (Wien’s constant = 2.898 x 10-3 m. K)​