Two metal rods 1 and 2 of same lengths have same temperature difference between their ends. Their thermal conductivities are K₁ and K₂ and cross sectional areas A₁ and A₂, respectively. If the rate of heat conduction in 1 is four times that in 2, then

A fluid is in streamline flow across a horizontal pipe of variable area of cross section. For this which of the following statements is correct?

The density of water at 20^oC is 998 kg/m³ and at 40^oC is 992 kg/m³. The coefficient of volume expansion of water is

A piece of iron is heated in a flame. It first becomes dull red then becomes reddish yellow and finally turns to white hot. The correct explanation for the above observation is possible by using