The thickness of a filament wire is 0.15 mm and length 10 cm. The filament ts heated to incandescence at 2000K. Calculate the energy radiated per second. If the power rating of the bulb is 40W, then calculate the relative emittance or surface emissivity.

Calculate the energy radiated per minute from a filament of an incandescent lamp at 3,000 K if the surface area is 10^(-4) m^(2) and its relative emitted is 0.425.

The energy radiated per hour from the surface of a filament 0.5 cm long and of radius 0.32 cm of an incandescent lamp at a certain temperature is 2.625xx10^(5) J. If the relative emittance of the surface is 0.8 calculate the temperature of the filament.

A bulb emits 2 xx 10^20 photons of wave length 400 nm in one second. Calculate the rate of emission of photons per second.

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) .

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 constant sigma is 6.0xx10^(-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 constant sigma is 6.0xx10^(-8)Wm^(-2)K^(-4) .

A filament of an evacuated light blue has length 10 cm, diameter 0.2mm and emissivity 0.2. Calculate the power it radiates at 2000 K ( sigma=5.67xx10^-8 J/m^2k^4 )

Steam at 373 K is passed through a tube of radius 10 cm and length 10 cm and length 2m . The thickness of the tube is 5mm and thermal conductivity of the material is 390 W m^(-1) K^(-1) , calculate the heat lost per second. The outside temperature is 0^(@)C .

Steam at 373 K is passed through a tube of radius 10 cm and length 10 cm and length 2m . The thickness of the tube is 5mm and thermal conductivity of the material is 390 W m^(-1) K^(-1) , calculate the heat lost per second. The outside temperature is 0^(@)C .