Physics

Problem

A star has a total luminosity of

3.8\times10^{26}\,\text{W}

and an effective surface temperature of

5800\,\text{K}

. Using

\sigma = 5.67\times10^{-8}\,\text{W\,m}^{-2}\text{K}^{-4}

, determine the radius of the star in metres (two significant figures).