Question

"As the Voyager spacecraft penetrated into the outer solar system, the illumination from the Sun declined. Relative to the situation at Earth, how bright is the sunlight at Jupiter? Jupiter's semi-major axis is 5.2 AU. Round your answer to two decimal places."

Answer 1

Answer:

$\frac{I_{2}}{I_{1}} = 0.04$

Explanation:

The intensity of a star noticed at a certain distance is inversely proportional to the square of distance. Then:

$I_{1}\cdot r_{1}^{2} = I_{2}\cdot r_{2}^{2}$

The intensity of the Sun in Jupiter relative to Earth is:

$\frac{I_{2}}{I_{1}} = \frac{r_{1}^{2}}{r_{2}^{2}}$

$\frac{I_{2}}{I_{1}} = \left(\frac{1\,AU}{5.2\,AU} \right) ^{2}$

$\frac{I_{2}}{I_{1}} = 0.04$