A pair of stars, Star C and Star D, have been observed. We see, by very close examination of the spectrum of each, that they are exactly the same type of star (same temperature, mass, radius, luminosity, etc.), but the amount of light that we get from Star D is 144 times as much as what we receive from Star C. Star D has been found to have a distance of 10 lightyears. As before, set up a ratio to calculate the distance of Star C. q1- How distant is Star C?

12 lightyears
24 lightyears
42 lightyears
100 lightyears
120 lightyears
144 lightyears
Star A is a Type 1 Cepheid with a period of 2 days, and has a known distance of 650 lightyears. Star B is a Type 2 Cepheid with a period of 100 days.

Q2: The luminosity of star A is:

0.001 times the luminosity of the Sun
the same luminosity as the Sun
100 times the luminosity of the Sun
1,000 times the luminosity of the Sun
10,000 times the luminosity of the Sun

Q3: The luminosity of star B is:

0.001 times the luminosity of the Sun
the same luminosity as the Sun
100 times the luminosity of the Sun
1,000 times the luminosity of the Sun
10,000 times the luminosity of the Sun