The total radiant energy per unit area, normal to the direction of incidence, received at a distance R from the centre of a star of radius r, whose outer surface radiates as a black body at a temperature T K is given by
(Where σ is Stefan's Constant)
1
\(\frac{4\pi \sigma {{r}^{2}}{{T}^{4}}}{{{R}^{2}}}\)
2
\(\frac{\sigma {{r}^{2}}{{T}^{4}}}{{{R}^{2}}}\)
3
\(\frac{\sigma {{r}^{2}}{{T}^{4}}}{4\pi {{r}^{2}}}\)
4
\(\frac{\sigma {{r}^{4}}{{T}^{4}}}{{{r}^{4}}}\)