Two planets are in a circular orbit of radius $$R$$ and $$4R$$ about a star. At a specific time, the two planets and the star are in a straight line. If the period of the closest planet is $$T,$$ then the star and planets will again be in a straight line after a minimum time:

1. $$(4)^2T$$
2. $$(4)^{\frac13}T$$
3. $$2T$$
4. $$8T$$
Subtopic: Â Kepler's Laws |
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From NCERT
NEET - 2022
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The time period of a geostationary satellite is $$24~\text{h}$$ at a height $$6R_E$$ $$(R_E$$ is the radius of the earth) from the surface of the earth. The time period of another satellite whose height is $$2.5R_E$$${}_{}$ from the surface will be:
 1 $$6\sqrt{2}~\text{h}$$ 2 $$12\sqrt{2}~\text{h}$$ 3 $$\dfrac{24}{2.5}~\text{h}$$ 4 $$\dfrac{12}{2.5}~\text{h}$$
Subtopic: Â Kepler's Laws |
Â 66%
From NCERT
NEET - 2019
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