There are three thermometers one in contact with the skin of the man other in between the vest and the shirt and third in between the shirt and coat. The readings of the thermomenters are `30^@C`,`25^@C` and `22^@C`, respectively. If the vest and the shirt are of the same thickness, the ratio of their thermal conductivities is

Two walls of thickness in the ratio 1:3 and thermal conductivities in the ratio 3:2 form a composite wall of a building. If the free surfaces of the wall be at temperatures 30^@C and 20^@C , respectively, what is the temperature of the interface?

Two walls of thickness in the ratio 1:3 and thermal conductivities in the ratio 3:2 form a composite wall of a building. If the free surfaces of the wall be at temperatures 30^@C and 20^@C , respectively, what is the temperature of the interface?

A wall consists of two layer, one of thickness 3 cm and other of 6 cm. the thermal conductivities of the materials of these layers are K and 3K respectively. The temperature of the outer surfaces of the two layers are -5^(@)C and 20^(@)C respectively. determine the temperature of the surface of contact of the two layers in the steady state.

Two rods A and B of same metal and of same cross-section have length in the ratio 1:2 One end of each rod is at O^(@)C and temperature of other ends are 30^(@)C and 40^(@)C respectively Which of the rod will have higher flow of heat ? .

The temperature difference between two ends of a 2 m long bar A is 40^@C and that between a 3 m long bar B of same area is 60^@C . If the rate of conduction of heat in two bars is same, calculate the ratio of coefficients of thermal conductivity of two bars.

Three rods A, B and C of the same length and same cross-sectional area are joined as shown. Their thermal conductivities are in the ratio 1:2:3/2. If the open ends of A and C are at 200^@ C and 18^@ C, respectively, then the temperature at the junction of A at steady state is

Two plates of equal areas are placed in contact wih each other. Their thickness are 2.0 cm and 5.0 cm respectively. The temperature of the external surface of the first plate is -20^(@)C and that of the external surface of the second plate is 20^(@)C . What will be the temperature of the current surface if the plates (i) are of the same material, (ii) have thermal conductivities in the ratio 2:5 .