The ends of two rods of different materials with their thermal conductivities, radii of cross-sections and lengths all are in the ratio $1:2$ are maintained at the same temperature difference. If the rate of flow of heat in the larger rod is $4\;cal/\sec $, that in the shorter rod in $cal/\sec $ will be

Heat current is maximum in which of the following (rods are of identical dimension)

The quantity of heat which crosses unit area of a metal plate during conduction depends upon

Three rods of identical area of cross-section and made from the same metal form the sides of an isosceles triangle $ABC$, right angled at $B$. The points $A$ and $B$ are maintained at temperatures $T$ and $\sqrt 2 T$ respectively. In the steady state the temperature of the point C is ${T_C}$. Assuming that only heat conduction takes place, $\frac{{{T_C}}}{T}$ is equal to

If the radius and length of a copper rod are both doubled, the rate of flow of heat along the rod increases ....... times

One likes to sit under sunshine in winter season, because