Consider a bright star in our night sky. Assume its distance from Earth is 45.9 light-years (ly) and its power output is 4.00 multiply.gif 1028 W, about 100 times that of the Sun.
(a) Find the intensity of the starlight at the Earth.
nW/m2
(b) Find the power of the starlight the Earth intercepts. One light-year is the distance traveled by the light through a vacuum in one year. (The radius of Earth is 6.37 multiply.gif 106 m.)
MW