Answer to Question #65912 in Astronomy | Astrophysics for Sudhanshu Raj
The mean free path of photons in stars is of the order of 0.2 cm. Show that the time taken for a photon to reach the surface of a star of radius 4 RQ is of the order of one million year.
We use the following expression
t = 16 x (Ro)2/(lc).
t = 16 x (6.96 x 108 m)2/(2 x 10-3 m x 3 x 108 m/s) = 412000 years