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 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

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 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)

A body which has a surface area 5.0 cm^(2) and a temperature of 727^(@)C radiater 300 J energy each minute. What is its emissivity? Stefan's Boltzmann's constat is 5.76 xx 10^(-8) Wm^(-2)K^(-4) .

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 )

A body which has a surface area 5.00 cm^(2) and a temperature of 727^(@)C radiated 300 j of energy each minute. What is the emissivity of body? Steafan's constant =5.67xx10^(-8) Wm^(-2) K^(-4) .

Calculate the temperature at which a perfect black body radiates at the rate of 1 W cm^(-2) , value of Stefan's constant, sigma = 5.67 xx 10^(-8) W m^(-2)K^(-4)

Calculate the temperature at which a perfect black body radiates at the rate of 1 W cm^(-2) , value of Stefan's constant, sigma = 5.67 xx 10^(-5) W m^(-2) K^(-8)

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) .

A hot body at 800^@C is radiating 500 J of energy per minute. Calculate the surface area of the body if emissivity is 0.23 and Stefan's constant is 5.67 xx 10^(-8) Wm^(-2) K^(.-4) .