The total radiant energy per unit area, normal to the direction of incidence, received at a distance `R` from the centre of a star of radius `r` whose outer surface radiates as a black body at a temperature `T K` is given by
(where `sigma` is Stefan's constant)

Radius of a star acting like perfect black body is R, then at what temperature the rate of radiation will be Q ? (Where sigma= Stefun - Boltzman constant)

The gravitational potential energy of a body at a distance r from the centre of the Earth is U where r gt R (radius of Earth). What is the weight of body at the point ?

What will be the power incident normally on unit area of spherical surface which is at distance R from the outermost surface of Sun of radius r at t^(@)C ? sigma= Stefan - Boltzmann's constant

A body with surface area (A), temperature (T) and emissivity (e) = 0.6 is kept inside a spherical black body. What will be the maximum energy radiated ? [ sigma is Stefan's constant]

A highly conducting solid sphere of radius R density rho and specific heat s is kept in an evacuted chamber. A parallel beam of thermal radiation of instensity I is incident on its surfcae Consider the sphere to be a perfectly black body and its temperature at certain instant considered at t =0 is T_(0) [Take Stefan's constant as sigma ] Answer the following questions based on above information The equation which gives the temperature T of the sphere as a function of time is .

A highly conducting solid sphere of radius R density rho and specific heat s is kept in an evacuted chamber. A parallel beam of thermal radiation of instensity I is incident on its surfcae Consider the sphere to be a perfectly black body and its temperature at certain instant considered at t =0 is T_(0) [Take Stefan's constant as sigma ] Answer the following questions based on above information The maximum attainable temperature of the sphere is .