Which of the following cylindrical rods will coduct most heat when their ends are maintained at the same steady temperatures?
Length $1\ m$, radius $1\ cm$
Length $1\ m$, radius $2\ cm$
Length $2\ m$, radius $1\ cm$
Length $2\ m$, radius $2\ cm$
Calculate the surface temperature of the planet, if the energy radiated by unit area in unit time is $5.67 \times 10^4\,watt$ : (Planet may be assumed to black body)
A cylinder of radius $R$ made of a material of thermal conductivity $K_1$ is surrounded by a cylindrical shell of inner radius $R$ and outer radius $2R$ made of material of thermal conductivity $K_2.$ The two ends of the combined system are maintained at two different temperatures. There is no loss of heat across the cylindrical surface and the system is in steady state. The effective thermal conductivity of the system is
If the temperature of the sun were to increase from $T$ to $2T$ and its radius from $R$ to $2R$, then the ratio of the radiant energy received on earth to what it was previously, will be
A long metallic bar is carrying heat from one of its ends to the other end under steady-state. The variation of temperature $\theta$ along the length $x$ of the bar from its hot end is best described by which of the following figures ?
A solid cube and a solid sphere of the same material have equal surface area. Both are at the same temperature $120\ ^oC$ , then