The power radiated by a black body is P and it radiates maximum energy at wavelength, $$\lambda $$₀ . If the temperature of the black body is now changed so that it radiates maximum energy at wavelength $${3 \over 4}{\lambda _0}$$, the power radiated by it becomes nP. The value of n is

A small sphere of radius ‘r’ falls from rest in a viscous liquid. As a result, heat is produced due to viscous force. The rate of production of heat when the sphere attains its terminal velocity, is proportional to

Two rods A and B of different materials are welded together as shown in figure. Their thermal conductivities are K₁ and K₂. The thermal conductivity of the composite will be

The bulk modulus of a spherical object is 'B'. If it is subjected to uniform pressure 'P', the fractional decrease in radius is