The emissive power of a sphere of area `0.07m^(2)` is 0.5 k cal/`m^(2)s`. The amount of heat radiated by the spherial surface in 20 second is

The emissive power of sphere of area 0.02 m^2 is 0.5 kcal//s-m^2 . What is the amount of heat radiated by the spherical surface in 20 seconds?

The emissive power of a sphere of area 0.02m^2 is 0.5 kcal s^-1m^-2 . What is the amount of heat radiated by the spherical surface in 20 seconds.

The effective area of a black body is 0.1 m^2 and its temperature is 1000 K . The amount of radiations emitted by it per min is –

The surface of a house hold radiator has an emissivity of 0.5 and an area of 1.5 m^(2) . The rate at which the radiation is emitted by then the radiator when its temperature is 47^(@)C will be nearly ( sigma=5.7xx10^(-8) Si units)

A body radiates heat at the rate of 5 cal/ m^(2)-s when its temperature is 227^(@)C . The heat radiated by the body when its temperature is 727^(@)C is

A black body at temperature 227^(@)C radiates heat at the rate of 5 cal/ cm^(2) , at a temperature of 27^(@)C , the rate of heat radiated per unit area per unit time in cal/ cm^(2) s, is

A body of mass 2 kg is being dragged with uniform velocity of 2 m / s on a rough horizontal plane. The coefficient of friction between the body and the surface is 0.20. The amount of heat generated in 5 sec is . (4.2"joule"//cal and g=9.8 m//s^(2))

A body of mass 2 kg is being dragged with uniform velocity of 2 m / s on a rough horizontal plane. The coefficient of friction between the body and the surface is 0.20. The amount of heat generated in 5 sec is . (4.2"joule"//cal and g=9.8 m//s^(2))

A body of mass 2 kg is being dragged with uniform velocity of 2 m / s on a rough horizontal plane. The coefficient of friction between the body and the surface is 0.20. The amount of heat generated in 5 sec is . (4.2"joule"//cal and g=9.8 m//s^(2))