A. Find the distance to a Sun-like star (L=3.8x1026watts) whose apparent brightness at Earth is 1.0 x10-10watt/m2
B. You measure the apparent brightness of a particular star to be 2.5 x 10-10watt/m2A parallax measurement shows the star's distance tobe 42 light-years, or about 4 x 1017meters. What is the stars luminosity?
C. Find the luminosity of a star whose apparent brightness is 1.03 x 10-8watt/m2, and whose distance is about 3 x 1018meters.