Earth is about 150 million kilometers from the Sun, and the apparent brightness of the Sun in our sky is about 1300 watts/m2. Use these two facts and the inverse square law for light to answer the questions.
a) Determine the apparent brightness that we would measure for the Sun if we were located half Earth's distance from the Sun.
b) Determine the apparent brightness that we would measure for the Sun if we were located twice Earth's distance from the Sun.
c) Determine the apparent brightness that we would measure for the Sun if we were located seven times Earth's distance from the Sun.