Gravitation - Result Question 7
7. The distance of two planets from the sun are $10^{13}$ and $10^{12}$ metres respectively. The ratio of time periods of these two planets is
[1988]
(a) $\frac{1}{\sqrt{10}}$
(b) 100
(c) $10 \sqrt{10}$
(d) $\sqrt{10}$
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Answer:
Correct Answer: 7. (c)
Solution:
- (c) $T^{2} \propto R^{3}$ (Kepler’s law)
$\frac{T_1^{2}}{T_2^{2}}=(\frac{10^{13}}{10^{12}})^{3} \Rightarrow \frac{T_1}{T_2}=10 \sqrt{10}$
