An electric bulb with tungsten filament having an area of `0.25 cm^(2)` is raised to a temperature of `3000 K`, when a current passes through it. Calculate the electrical energy being consumed in watt, if the emissivity of the filament is 0.35. Stefan's constant, `sigma = 5.67 xx 10^(-5) erg^(-1) cm^(-2) K^(-4)`. If due to fall in main voltage the fialment temperature falls to 2500 K, what will be wattage of the bulb?

An electric bulb with a tungsten filament has an area of 0.20 cm^2 and is raised to a temperature of the bulb to 3000 K emissivity of the filament is 0.40 and Stefan's constant is 5.7 xx 10^(-5) erg s^(-1) cm^(-1) K^(-4) . The electrical energy consumed by the bulb is E_1 watt. If due to fall in voltage, the temperature of the filament falls to 2800 K, then the wattage of the bulb is E_2 watt. Calculate the value of E_1 - E_2 , close to nearest integer.

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 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)

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 metallic ball of surface area 300 cm^2 at a temperature of 227^@C is placed in a container at 27^@C . Calculate the rate of loss of heat radiation by the ball if emissivity of ball is 0.3, sigma = 5.67 xx 10^(-5) erg cm^(-2) s^(-1) K^(-4) .

A thin brass rectangular sheet of sides 15.0 cm and 10.0 cm is heated in a furnace to 500^@C and then taken out. Calculate the electric power that is needed to maintain the sheet at this temperature, given that the emissivity is 0.250. (Stefan-Boltzmann 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 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) .

Consider the sun to be a perfect sphere of radius 6.8 xx 10^(8)m . Calculate the energy radiated by sun in one minute. Surface temperature of the sun = 6200 K . Stefan's constant = 5.67 xx 10^(-8) J m^(-2) s^(-1) K^(-4) .