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 metal ball of surface area 200 cm^(2) and temperature 527^(@)C is surrounded by a vessel at 27^(@)C . If the emissivity of the metal is 0.4, then the rate of loss of heat from the ball is (sigma = 5.67 xx10^(-8)J//m^(2)-s-k^(4))

A blackbody of sarface area 10cm^(2) is heated to 127^(@)C and is suspended in a room at temperature 27^(@)C calculate the initial rate of loss of heat from the body to the room.

A body of emissivity (e = 0.75) , surface area of 300cm^(2) and temperature 227^(@)C is kept in a room at temperature 27^(@)C . Calculate the initial value of net power emitted by the body.

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) .

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

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?

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) .