Answer:
a. [tex]3.95\times10^{26} [/tex]W
Explanation:
[tex]T[/tex] = temperature of the surface of sun = 5800 K
[tex]r[/tex] = Radius of the Sun = 7 x 10⁸ m
[tex]A[/tex] = Surface area of the Sun
Surface area of the sun is given as
[tex]A = 4\pi r^{2} \\A = 4(3.14) (7\times10^{8})^{2}\\A = 6.2\times10^{18} m^{2}[/tex]
[tex]e[/tex] = Emissivity = 1
[tex]\sigma[/tex] = Stefan's constant = 5.67 x 10⁻⁸ Wm⁻²K⁻⁴
Using Stefan's law, Power output of the sun is given as
[tex]P = \sigma e AT^{4} \\P = (5.67\times10^{-8}) (1) (6.2\times10^{18}) (5800)^{4}\\P = 3.95\times10^{26} W[/tex]