Question-answer on Universe | Learn Physics

 Question-answer on Universe

Question: Luminosity of a star is is 10,000 times that of the sun and its surface temperature is 3000 K. assuming the surface temperature of sun to be 6000 K, compare the radius of the star with that of the sun.

 

Solution:

Let R, R₁ = radius of sun and star respectively.

L,L₁ = the luminosity of sun and star respectively and T, T₁ = be their temperatures. Then

L₁ = ∂T₁² × 4πR₁²  and  L =∂T² × 4πR²

                                                                      L₁/L = (T₁/T)⁴(R₁/R)²

                                                               =400