Thermal Propert...

A lead bullet, of initial temperature $$27 ^ { \circ } C$$ and speed $$'v'$$ kmph pnetrates into a solid object and melts. If $$50\%$$ of the kinetic energy is used to heat it, The value of $$V$$ is kmph is (for leads melting point  = 600 K, latent heat of fusion = $$2.5 \times 10 ^ { 4 } J$$ $$\mathrm { Kg } ^ { - 1 }$$ : specific heat = $$125 J$$ $$k g ^ { - 1 } K ^ { - 1 }$$

If water at $$0^0C$$, kept in a container with an open top, is placed in a large evacuated chamber,

A body at $$50^{0}C$$ cools in a surrounding maintained at $$30^{0}C$$. The temperature at which the rate of cooling is half that of beginning is:

When $$2 gm$$ of gas is introduced into an evacuated flask kept at $$25^oC$$ the pressure is found to be one atmosphere. If $$3 gm$$ of another gas added to the same flask the pressure becomes $$1.5$$ atmospheres. The ratio of the molecular weights of there gases will be

In a waterfall the water falls from a height of 100 m. If the entire energy of water is converted into heat. The rise in temperature of water will be:

A real gas most closely approaches the behaviour of an ideal gas at :

Glaciers melt:

Two metal sphere have radii $$r$$ and $$2r$$ and they emit thermal radiation with maximum intensities at wavelength $$\lambda$$ and $$2 \lambda$$. The respective ratio of the radiant energy emitted  by them per second will be

The heat transferred by the radiator of a refrigerator is

If the ratio of the coefficient of thermal conductivity of silver and copper is $$10: 9$$, then the ratio of the lengths up to which was will melt in Ingen Hauz experiment will be