Heat given to a body, which raises its temperature by 1^oC is known as:

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:

Two metallic spheres S₁ and S₂ are made of the same material and have got identical surface finish. The mass of S₁ is thrice that of S₂. Both spheres are heated to  same high temperature and placed in the same room having lower temperature . The ratio of the initial rate of cooling of S₁ to that of S₂ is:

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 :

The wavelength of radiation emitted by a body depends upon:

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 black body at a temperature of 227^oC radiates heat at the rate of 20 cal m^-2s^-1. When its temperature rises to 727^oC, the rate of heat radiated 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:

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:

The intensity of radiation emitted by the sun has its maximum value at a wavelength of 510 nm and that emitted by the North Star has the maximum value at 350 nm. If these stars behave like black bodies, then the ratio of the surface temperature of the sun and the North Star is: