Thermal Propert...

The coefficients of thermal conductivity of copper, mercury and glass are respectively K_c, K_m and K_g, such that K_c > K_m > K_g. if the same quantity of heat is to flow per second per unit area of each and corresponding temperature gradients are X_c, X_m and X_g, then

If two metallic plates of equal thickness and thermal conductivities K₁ and K₂ are put together face to face and a common plate is constructed, then the equivalent thermal conductivity of this plate will be

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

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/s, that in the shorter rod in cal/s will be

Two spheres of different materials one which double the radius and one–fourth wall thickness of the order, are filled with ice. If the time taken for complete melting ice in the large radius one is 25 minutes and that for smaller one is 16 minutes, the ratio of thermal conductivities of the materials of larger sphere to the smaller sphere is

Woolen clothes are used in winter season because woolen clothes

Two identical rods of copper and iron are coated with wax uniformly. When one end of each is kept at temperature of boiling water, the length upto which wax melts are 8.4 cm and 4.2 cm respectively. If thermal conductivity of copper is 0.92, then thermal conductivity of iron is

Mud houses are cooler in summer and warmer in winter because

The temperature of hot and cold end of a 20 cm long rod in thermal steady state are at 100^oC and 20^oC respectively. temperature at the centre of the rod is

two bars of thermal conductivities K and 3K and lengths 1 cm and 2 cm respectively have equal cross–sectional area, they are joined lengths wise as shown in the figure. If the temperature at the ends of this composite bar is 0^oC and 100^oC respectively (see figure), then the temperature ϕ of the interface is