The filament of an evacuated light bulb has a length 10 cm, diameter 0.2 mm and emissivity 0.2. then the power it radiates at `1727^(@)C` is [`sigma=5.67xx10^(-8)` SI units]

A spherical black body of 5 cm radius is maintained at a temperature of 327^(@)C . Then the power radiated will be (sigma=5.7xx10^(-8)"SI unit")

An incandesent light bulb has a tungsten filament that is heated to a temperature 3 xx 106(3)K when an electric current passes through it If the surface area of the filament is approximately 10^(-4)m m^(2) and it has an emissivity of 0.3 the power radiated by the bulb is nearly (sigam = 5.67 xx 10^(-8) W m^(-2) K^(-4)) .

A bulb made of tungsten filament of surface are a 0.5cm^(2) is heated to a temperature 3000 K when operatred at 220V . The emissivity of the filament is e=0.35 and take sigma=5.7xx10^(-8)mks units . Then calculate the wattage of the bulb (in watt)

The surface of a house hold radiator has an emissivity of 0.5 and an area of 1.5 m^(2) . The rate at which the radiation is emitted by then the radiator when its temperature is 47^(@)C will be nearly ( sigma=5.7xx10^(-8) Si units)

The emissivity and surface area of tungsten filament of an electric bulb are 0.35 and 0.25 xx 10^(-4) metre^(2) respectively. The operating temperature of filament is 3000 K. If sigma = 5.67 xx 10^(-8) watt melre^(-2) K^(-4) , then power of bulb is approximately:

A bulb made of tungsten filament of surfece area 0.5 cm^2 is heated to a temperature 3000K when operated at 220V.The emissivity of the filament is in=0.35 and take sigma=5.7xx10^-8 mks units. Then the power of the bulb is,

How much energy in radiated per minute from the filament of an incandescent lamp at 3000 K, if the surface area is 10^(-4)m^(2) and its emissivity is 0.4 ? Stefan's constant sigma = 5.67 xx 10^(-8) Wm^(-2)K^(-4) .

The operating temperature of a tungesten filament in an indandescent lamp is 2000 K and its emissivity is 0.3 . Find the surface area of the filament of a 25 watt lamp. Stefan's constant sigma = 5.67xx10^(-8) Wm^(-2)K^(-4)

A 500W lamp loses all of its energy by emission of radiation from the surface. If the area of the surface of the filament is 2.0cm^(2) and its emissivity is 0.5, estimate the temperature of its filameiit. Given that Stefan constant, sigma =5.7xx10^(-8)W//m^(2)K^(4). Neglect radiation receivedby lamp from surrounding.