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

What will be the power incident normally on unit area of spherical sur

1.	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
Answer» `(r^(2)SIGMA(t+273^(4)))/(4piR^(2))` `(16pi^(2)r^(2)sigmat^(4))/(R^(2))` `(r^(2)sigma(t+273)^(4))/(R^(2))` `(4pir^(2)sigmat^(4))/(R^(2))` Solution :From Stefan - BOLTZMANN law, `P=AesigmaT^(4)` `:.P=4pir^(2)sigmaT^(4)""[becauseA=4pir^(2),e=1]` POWER INCIDENT per unit area, `=(P)/(4piR^(2))=(4pir^(2)sigmaT^(4))/(4piR^(2))=(r^(2)sigma(t+273)^(4))/(R^(2))`