A rectangular film of liquid is extended from (4 cm $$ \times $$ 2 cm) to (5 cm $$ \times $$ 4 cm). If the work done is 3 $$ \times $$ 10^$$-$$4 J, the value of the surface tension of the liquid is

Two identical bodies are made of a material for which the heat capacity increases with temperature. One of these is at 100^oC, while the other one is at 0^oC. If the two bodies are brought into contact, then, assuming no heat loss, the final common temperature is

Three liquids of densities $$\rho $$₁, $$\rho $$₂  and $$\rho $$₃ (with $$\rho $$₁ > $$\rho $$₂ > $$\rho $$₃), having the same value of surface tension T, rise to the same height in three identical capillaries. The angles of contact $$\theta $$₁, $$\theta $$₂ and $$\theta $$₃ obey

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