Thermal Resistance

Three rods of material 'x' and three rods of materialy are connected as shown in All the rods are of identical length and cross section If the end A is maintained at 60^(@)C and the junction E at 10^(@0C find effective Thermal Resistance Given length of each rod =1 area of cross-section =A conductivity of x=K and conductivity of y =2K .

Assertion : Greater is the coefficient of thermal conductivity of a material, smaller is the thermal resistance of a rod of that material. Reason : Thermal resistance is the ratio of temperature difference between the ends of the conductor and rate of flow of heat.

Four rods of material X and three rods of material Y are connected as shown in figure. All the rods are of identical lengths and cross-sectional area. Given thermal resistance of rod of material X, R_(x) = R and thermal conductivities of materials are related by relation K_(Y) = 2K_(X) . {:(,"Column-I",,"Column-II"),((A),"Thermal resistance between B and E" ,(p),(500)/(13).^(@)C ),((B),"Thermal resistance between A and F" ,(q),(700)/(13).^(@)C ),((C),"Temperature of junction B" ,(r),(2R)/(3)), ((D),"Temperature of junction D" ,(s),(13R)/(6)):}

Assertion : A conducting rod is placed between boiling water and ice. If rod is broken into two equal parts and two parts are connected side by side, then rate of melting of ice will increase ot four times. Reason : Thermal resistance will become four times.

Statement I: The thermal resistance of a multiple later is equal to the sum of the thermal resistance of the individual laminas. Statement II: Heat transferred is directly proportional to the temperature gradient in each layer.

The ratio of the coefficient of thermal conductivity of two different materials is 5 : 3 . If the thermal resistance of the rod of same thickness resistance of the rods of same thickness of these materials is same, then the ratio of the length of these rods will be

The thermal conductivity of two materials are in the ratio 1 : 2. What will be the ratio of thermal resistances of rods of these materials having length in the ratio 1 :2 and area of cross-section in the ratio 1:2 :

A cylindrical rod of aluminium is of length 20 cm and radius 2 cm. The two ends are maintained at temperatures of 0^(@)C and 50^(@)C the coefficient of thermal conductivity is (0.5" cal")/(cm xx sec xx ""^(@)C) . Then the thermal resistance of the rod in ("cal")/(sec xx ""^(@)C) is

Two rods A and B of same cross-sectional area A and length l are connected in series between a source (T_(1)=100^(@)C) and a sink (T_(2)-0^(@)C) as shown in figure. The rod is laterally insulated. The ratio of the thermal resistance of the rods is

Two rods A and B of same cross sectional are A and length l connected in series between a source (T_(1) =100^(@)C) and a sink (T_(2) =0^(@)C) as shown in The rod is laterally insulated The ratio of thermal resistance of the rod is .