An indirectly heated filament is radiating maximum energy of wavelength `2.16xx10^-5cm`. Find the net amount of heat energy lost per second per unit area, the temperature of the surrounding air is `13^@C`. Given `b=0.288cm-K.sigma=5.77xx10^-5erg//s-cm^(2)-K^(4)`).

A heated filament of a bulb is radiating maximum energy at wavelength 3.14 xx 10^(-5) cm. Determine the total amount of energy lost per second per unit area by the filament if the temperature of the surrounding air is 20^@C . Take, b = 0.288 cm K sigma = 5.77 xx 10^(-5) erg s^(-1) cm^(-2) K^(-4)

Two stars radiate maximum energy at wavelengths 3.6xx10^(-5)cm and 4.8xx10^(-5)cm respectively. The ratio of their temperature is

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

How much energy will be emitted from a furnace at 3000K temperature active as a perfect black body per unit area in 1 hour ? (sigma=5.7xx10^(-8)" Wm"^(-2)K^(-4))

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 copper sphere has a surface area of 3.142 xx 10^-2m^2 and its emissivity is 0.018. Find the energy lost by the sphere per second when its temperature is 100^@C . ( sigma = 5.67 xx 10^-8 W/m^2k^4 .)

At what temperature will the filament of 100 W lamp operate if it is supposed to be perfectly black of area 1 cm^(2) . Given sigma = 5.67 xx 10^(-5) erg cm^(-2) s^(-1) K^(-4) .

Calcualte the maximum amount of heat which may be lost per second by radiation from a sphere of 10 cm in diameter and at a temperature of 227^(@) C when placed in an encloser at a temperature of 27^(@) C. sigma = 5.7xx10^(-8)Wm^(-2)K^(-4) .

Assume that the total surface area of a human body is 1-6m^(2) and that it radiates like an ideal radiator. Calculate the amount of energy radiates per second by the body if the body temperature is 37^(@)C . Stefan contant sigma is 6.0xx10^(-s)Wm^(-2)K^(-4) .