An astronomer measures a star’s luminosity to be and its surface temperature to be

PHYSICS · Subjective · A Level · Physics · Astrophysics · Astrophysics

Problem

An astronomer measures a star’s luminosity to be

1.2\times10^{28}\,\text{W}

and its surface temperature to be

9500\,\text{K}

. Given the Sun’s luminosity

L_{\odot}=3.9\times10^{26}\,\text{W}

and radius

R_{\odot}=6.96\times10^{8}\,\text{m}

, determine the radius of the star in units of the solar radius

R_{\odot}

. Use

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