Find the surface area of black body maintained at `127^@C` radiating energy at the rate of `1459.2 J//sec`.

Compare the rates of emission of heat by a black body maintained at 727^@C and at 227^@C , if the black bodies are surrounded by an enclosure (black) at 27^@C . What would be the ratio of their rates of loss of heat.

The rate of change of surface area of a sphere of radius r when the radius is increasing at the rate of 2 cm/sec is proportional to: a) 1/r b) r c) 1/r^2 d) r^2

The rate of change of surface area of a sphere of radius r when the radius is increasing at the rate of 2 cm/sec is proportional to a)1/r b)1/r^2 c)r d)r^2

A body radiates energy 5 W at a temperature of 127^(@)C . If the temperature is increased to 927^(@)C , then it radiates energy at the rate of

A body having surface area 5 cm^2 and temperature of 727^@C radiates 300 J of energy per minutes. What is its emissivity?(Stefan's constanta sigma=5.7xx10^-8 J//mk^4 )

Assuming that the sun radiates as a black body, calculate the energy radiated per minute by unit area of its surface. Surface temperature of the sun = 5727^@C and Stefan's constant = 5.7 xx10^-8 Jm^-2K^-4s^-1 .

A black body radiates 20 W at temperature 227^(@)C . If temperature of the black body is changed to 727^(@)C then its radiating power wil be

The power radiated by a black body is P, and it radiates maximum energy around the wavelength lambda_(0) . If the temperature of the black body is now changed so that it radiates maximum energy around a wavelength 3lambda_(0)//4 , the power radiated by it will increase by a factor of

Which body radiates heat energy at higher rate? Hotter or cooler.