Heat TransferMedium
Question
Suppose the sun expands so that its radius becomes 100 times its present radius and its surface temperature becomes half of its present value. The total energy emited by it then will increase by a factor of :
Options
A.104
B.625
C.16
D.16
Solution
E = σT4, here E is energy radiated per area. Total energy emitted = σT4 × A Total energy emitted by sun after expansion
σ ×
× 100 × 100 A [where radius becomes 100 times,area becomes 1002 times]
σT4 ×
× 100 × 100 = 625 × σT4A
So, total energy emitted is 625 times.
σ ×
× 100 × 100 A [where radius becomes 100 times,area becomes 1002 times] σT4 ×
× 100 × 100 = 625 × σT4A So, total energy emitted is 625 times.
Create a free account to view solution
View Solution FreeMore Heat Transfer Questions
Calculate the energy radiated per minute from the filament of an incandascent lamp at 2000K if the surface area is 5 ...Rods x and y of equal dimensions but of different materials are joined as shown in figure. Temperatures of end points $A...A spherical body with an initial temperature T1 is allowed to coll in surrounding at temperature T0(< T1). The mass o...If the rate of emission of radiation and the rate of absorption by surface of a body are same then the temperature of bo...Two identical square rods of metal are welded end to end as shown in figure (a) 20 calories of heat flows through it in ...