A black body has maximum wavelength λ_m at 2000 K. Its corresponding wavelength at 3000 K will be

Assuming the sun to be a spherical body of radius R at a temperature of TK, evaluate the total radiant power, incident on earth, at a distance r from the sun ?

( r₀ is the radius of the earth and  is the Stefan's constant.)

Heat current is maximum in which of the following (rods are of identical dimension) ?

A thermometer has wrong calibration.  It reads the melting point of ice as - 10^o C, the temperature of boiling point of water on this scale is :

Water of volume 2 litres in a container is heated with a coil of 1 KW at 27^oC. The lid of the container is open and energy dissipates at a rate of 160 Js^-1. In how much time, temperature will rise from 27^oC to 77^oC?  (Given that the specific heat of water is 4.2 kJ kg^-1)

Two spheres of the same material have radii 1 m and 4 m and temperatures 4,000 K and 2,000 K respectively. The ratio of the energy radiated per second by the first sphere to that by the second is:

The earth radiates in the infra-red region of the spectrum. The spectrum is correctly given by :

If boiling point of water is 95^oF, what will be theb reading at Celsius scale ?

A piece of blue glass heated to a high temperature and a piece of red glass at room temperature, are taken inside a dimly lit room, then:

540 g of ice at 0^o C is mixed with 540 g of water at 80^o C.  The final temperature of the mixture is