Calculate the amount of heat radiated per second by a body of surface area `12cm^(2)` kept in thermal equilibrium in a room at temperature `20^(@)C` The emissivity of the surface `=0.80` and `sigma=6.0xx10^(-s)Wm^(-2)K^(-4)` .

Calculate the amount of heat radiated per second by a body of surface are 10 cm^(2) kept in thermal equilibrium in a roomat temperature 27^(@)C . The emissivity of the surface = 0.80 and Stefan's constant sigma ~= 6 xx 10^(-8) W//m^(2) K^(4)

A body of surface are 15xx10^(-3)m^2 emits 0.3 kcal in 40 second at a temperature 70^(@)C . The emissive power of the surface at that temperature is

A room heater is made up of thin wall tubes of copper, each 1.0 m long and 4.0 cm in diameter. Hot water aet 77^(@)C circulates constantlyh through the tubes. Calculate the amount of heat radiated per second in a room where the average temperature is 27^(@)C . The emissivity of copper =0.8 and Stefan's contant =5.67xx10^(-8)Wm^(-2)K^(-1)

The power of black body at temperature 200 K is 544 W .Its surface area is (sigma=5.67xx10^(-8)Wm^(-2)K^(-2))

A body having a surface area of 50cm^2 radiates 300J of energy per minute at a temperature of 727^(@)C . The emissivity of the body is ( Stefan's constant =5.67xx10^(-8)W//m^2K^4 )

The energy of 6000 J is radiated in 10 minutes by a body of surface area 200 cm^(2) . Find the emissive power of the body.

Calculate the maximum amount of heat which may be lost per second by radiation by a sphere 14cm in diameter at a temperature of 227^(@)C , when placed in an enclosure at 27^(@)C . Given Stefan's constant = 5.7 xx 10^(-8)Wm^(-2)K^(-4) .

A body of surface area 10 cm^(2) and temperature 727 ^(@) C emits 600 J of enrgy per minute. Find its emissivity.

The radiant power of a furnace of surface area of 0.6m^(2) is 34.2KW The temperature of the furance s [sigma = 5.7 xx 10^(-8) Wm^(-2) K^(-4) .