A rod of 40 cm in length and temperature difference of `80^(@)C` at its two ends. Another rod B of length 60cm and of temperature difference `90^(@)C`, having the same area of cross-section. If the rate of flow of heat is the same, then the ratio of their thermal conductivities will be

The ratio of thermal conductivity of two rods of different material is 5:4. The two rods of same area of cross-section and same thermal resistance will have the lengths in the ratio

The ratio of thermal conductivity of two rods of different material is 5 : 4 . The two rods of same area of cross-section and same thermal resistance will have the lengths in the ratio

The ratio of thermal conductivity of two rods of different material is 5 : 4 . The two rods of same area of cross-section and same thermal resistance will have the lengths in the ratio

The ends of two rods of different materials with their thermal conductivities, radii of cross sections and lengths all 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, the rate of flow of heat in the shorter rod will be

Heat is flowing through two cylindrical rods of the same material . The diameters of the rods are in the ratio 1:2 and the lengths in the ratio 2:1.If the temperature difference between the ends be the same ,then the ratio of the rate of flow if heat through them will be ?

Two cylindrical rods of the same material have the same temperature difference between their ends. The ratio of the rates of flow of heat through them is 1 : 8. The radii of the rods are in the ratio 1 : 2. What is the ratio of their lengths ?

The quantity of heat flowing for 10 seconds through a rod of length 40 cm, area 50 cm^(2) is 200 J. If the temperature difference at the ends of the rod is 80^(@) C, then coefficient of thermal conductivity of the rod in Wm^(-1)K^(-1) is