Home › MCQs › TEEN Physics › Question #1054
Back to Questions
TEEN Physics QUESTION #1054
Question 1
Martian orbit radius \(\approx4\times\) Mercury orbit radius. Martian year \(=687\) Earth days. Length of 1 year on Mercury:
  • 172 earth days
  • 124 earth days
  • 88 earth days✔️
  • 225 earth days
Correct Answer Explanation
Kepler's 3rd law: \(T^2\propto r^3\). \(\frac{T_{Mer}^2}{T_{Mar}^2}=\frac{r_{Mer}^3}{r_{Mar}^3}=\frac{1}{4^3}=\frac{1}{64}\). \(T_{Mer}=\frac{T_{Mar}}{8}=\frac{687}{8}\approx86\approx88\ \text{earth days}\).