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 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 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 metal ball of mass 2kg is heated means of a 40W heater in a room at 25^(@)C . The temperature of the ball beomes steady at 60^(@)C . Find the rate of loss of heat to the surrounding when the ball is at 60^(@)C .

Calculate the amount of heat radiated per second by a body of surface are 10 cm^(2) kept in thermal equilibrium in a roomat temperature 27^(@)C . The emissivity of the surface = 0.80 and Stefan's constant sigma ~= 6 xx 10^(-8) W//m^(2) K^(4)

The power of black body at temperature 200 K is 544 W .Its surface area is (sigma=5.67xx10^(-8)Wm^(-2)K^(-2))

If the rate of emission of energy from a star is 2.7 xx 10^(36) J/ sec, the rate of loss of mass in the star will be

The radiant power of a furnace of surface area of 0.6m^(2) is 34.2KW The temperature of the furance s [sigma = 5.7 xx 10^(-8) Wm^(-2) K^(-4) .

A metallic sphere having radius 0.08 m and mass m = 10 kg is heated to a temperature of 227^(@)C and suspended inside a box whose walls ae at a temperature of 27^(@)C . The maximum rate at which its temperature will fall is:- (Take e =1 , Stefan's constant sigma = 5.8 xx 10^(-8) W//m^(-2)K^(-4) and specific heat of the metal s = 90 cal//kg//deg J = 4.2 "Joules"//"Calorie")