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:

Water falls from a height of 500 m.  What is the rise in temperature of water at the bottom if the whole energy is used up in heating water ?

An ungraduated thermometer of uniform bore is attached to a centimetre scale and is found to read 10.3 cm in melting ice, 26.8 cm in boiling water and 6.5 cm. in freezing mixture.  The temperature of the freezing mixture will be :

A block of steel heated to 100^oC is left in a room to cool. Which of the curves shown in the figure, represents the correct behaviour ?

       

A spherical black body with a radius 12 cm radiates 450 W power at 500 K. If the radius were halved and the temperature doubled, the power radiated in watt would be:

For a gas, the difference between two principal specific heats is 4150 J kg^-1 K^-1 .  What is the specific heat of the gas at constant volume if the ratio of specific heats is 1.4 ?

An ideal black body at room temperature is thrown into a furnace. It is observed that:

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 ?

       

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

In determining the temperature of a distant star, one makes use of: