Calculate the energy radiated in 30 seconds by perfectly black sphere of radius5cm maintained at `127^@C`. (Stefan's constant `s = 5.7 xx 10^-8 J//m^2sk^4)`

Calculate the energy radiated in one minute by a black body of surface area 100 cm^2 when it is maintained at 227^@C ( sigma= 5.67 xx 10^-8 J/m^2sK^4 )

Assuming that the sun radiates as a black body, calculate the energy radiated per minute by unit area of its surface. Surface temperature of the sun = 5727^@C and Stefan's constant = 5.7 xx10^-8 Jm^-2K^-4s^-1 .

Calculate the energy radiated is one minutes by a black body of surface area 400cm^2 ,when it is maintained at 127^@C .

Calculate the energy radiated is one minute by a blackbody of surface area 200 cm^2 at 127^@C ( sigma = 5.7 xx 10^-8 Jm^-2s^-1K^-4 )

What is the temperature at which a black body radiates heat at the rate of one kilowatt per unit area ? (Stefan 's constant sigma = 5.7 xx 10^(-8) S.Iunits)

A 100 watt filament loses all its power by radiation when it is heated to a temperature of 2500 K. If the diameter of the filament is 0.2 mm and the surface emissivity of the filament is 0.5, find the length of the filament. (Stefan's constant sigma = 5.67 xx10^-8 W/m^2k^4 )

A body having surface area 5 cm^2 and temperature of 727^@C radiates 300 J of energy per minutes. What is its emissivity?(Stefan's constanta sigma=5.7xx10^-8 J//mk^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 )