Answer:[tex]8.18\times10^{26}W[/tex]
Total Power emitted in space by the star is given by:
[tex]P=\sigma T^4 A[/tex]
where total power emitted per unit area is given by [tex]\sigma T^4[/tex]
where T is the temeprature in Kelvins and [tex] \sigma=5.7\times10^{-8}Wm^2K^4[/tex]
A is the surface area of spherical star. [tex]A =4\pi r^2[/tex].
It is given that:
[tex]T=6500 K\\ r=8.0\times10^8m[/tex]
Insert the values in the formula for total power emitted:
[tex]P=5.7 \times10^{-8}\times 6500^4 \times 4\times 3.14 \times (8.0\times10^8)^2=8.18\times10^{26}W[/tex]