Question #65912

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.

Expert's answer

We use the following expression

t = 16 x (Ro)2/(lc).

Then,

t = 16 x (6.96 x 108 m)2/(2 x 10-3 m x 3 x 108 m/s) = 412000 years

t = 16 x (Ro)2/(lc).

Then,

t = 16 x (6.96 x 108 m)2/(2 x 10-3 m x 3 x 108 m/s) = 412000 years

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