A body cools from a temperature 3T to 2T in 10 minutes. The room temperature is T. Assume that Newton's law of cooling is applicable. The temperature of the body at the end of next 10 minutes will be

Coefficient of linear expansion of brass and steel rods are $$\alpha $$₁ and $$\alpha $$₂. Lengths of brass and steel rods are $$l$$₁ and $$l$$₂ respectively. If ($$l$$₁ $$-$$ $$l$$₂) is maintained same at all temperatures, which one of the following relations holds good?

Two non-mixing liquids of densities $$\rho $$ and n$$\rho $$ (n > 1) are put in a container. The height of each liquid is h. A solid cylinder of length L and density d is put in this container. The cylinder floats with its axis vertical and length $$\rho $$L ($$\rho $$ < 1) in the denser liquid. The density d is equal to

A piece of ice falls from a height h so that it melts completely. Only one-quarter of the heat produced is absorbed by the ice and all energy of ice gets converted into heat during its fall. The value of h [Latent heat of ice is $$3.4 \times {10^5}$$ J/kg and g = 10 N/Kg]