Three cubes of sides 1,2,3 cm are at constant temperature of `100^(@)C`. Then the amount of heat lost per second by them are in the ratio

A sphere of radius 15 cm is at a temperature of 215^@C . Find the maximum amount of heat which may be lost per second by radiation when the sphere is placed in an enclosure at 25^@C . Take, sigma = 5.67 xx 10^(-8) Wm^(-2) K^4

Two identical spheres A and B are suspended in an air chamber which is maintained at a temperature of 50^@C . Find the ratio of the heat lost per second from the surface of the spheres if a. A and B are at temperatures 60^@C and 55^@C , respectively. b. A and B are at temperatures 250^@C and 200^@C , respectively.

Two identical spheres A and B are suspended in an air chamber which is maintained at a temperature of 50^@C . Find the ratio of the heat lost per second from the surface of the spheres if a. A and B are at temperatures 60^@C and 55^@C , respectively. b. A and B are at temperatures 250^@C and 200^@C , respectively.

Three black bodies A, B and C in the form of cubes of sides in the ratio 3 : 4 : 5 are kept at the same high temperature. The ratio of the quantity of heat lost per second by A, B and C will be

The lengths and radii of two rods made of same material are in the ratios 1 : 2 and 2 : 3 respectively. If the temperature difference between the ends for the two rods be the same, then in the steady state, the amount of heat flowing per second through them will be in the ratio

The lengths and radii of two rods made of same material are in the ratios 1 : 2 and 2 : 3 respectively. If the temperature difference between the ends for the two rods be the same, then in the steady state, the amount of heat flowing per second through them will be in the ratio

A rod of 1m length and area of cross-section 1cm^(2) is connected across two heat reservoirs at temperature 100^(@)C and 0^(@)C as shown. The heat flow per second through the rod in steady state will be [Thermal conductivity of material of rod =0.09kilocalm^(-1)s^(-1)('^(@)C) ]

Masses of three wires are in the ratio 1:3:5 . Their lengths are in the ratio 5:3:1 . When they are connected in series to an external source, the amounts of heats produced in them are in the ratio