A spherical body of area A and emissivity e = 0.6 is kept inside a perfectly black body. Energy radiated per second by the body at temperature T is:

A wall has two layers A and B each made of a different material. Both layers have the same thickness, the thermal conductivity of the material of A is twice that of B. Under thermal equilibrium, the temperature difference across the wall is 36^oC. The temperature difference across the layer A will be:

If the temperature of the sun  increases from T to 2T and its radius from R to 2R, then the ratio of the radiant energy received on earth to what it was previously, 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.)

A block of ice at - 10^oC is slowly heated and converted to steam at 100^oC. Which of the following curves represents the phenomenon qualitatively ?

A copper block of mass 2.5 kg is heated in a furnace to a temperature of 500^o C and then placed on a large ice block.  The maximum amount of ice that can melt is :
(sp.heat of Cu = 0.39 J/gm/^o C and heat of diffusion of water = 335 J/gm)

Three disc A, B and C having radii 2 m, 4 m and 6 m respectively are coated with carbon black on their outer surfaces. The wavelengths corresponding to maximum intensity are 300 nm, 400 nm and 500 nm respectively. The powers radiated  are Q_A, Q_B and Q_C respectively.

The volume of a liquid is 830 m³ at 30^o C and it is 850 m³ at 90^o C.  The coefficient of volume expansion of the liquid is 

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

Variation of radiant energy emitted by sun, filament of tungsten lamp and welding arc as a function of its wavelength is shown in figure. Which of the following options is the correct match ?