26.Which of the following carries anomalous expansion?

27.Which of the following quantities is zero on an average for the molecules of an ideal gas in equilibrium?

28.During severe winter in the low temperature zones of the world, the superficial parts of the lakes are frozen leaving water below. That the freezing at the bottom is prevented because:

29.The ratio of thermal capacities of two spheres A and B, if their diameters are in the ratio 1: 2, densities in the ratio 2: 1 and the specific heats in the ratio of 1: 3 will be: