The radius of Martian orbit around the sun is about \(4\) times the radius of the orbit of mercury. The Martian year is \(687\) earth days. Then which of the following is the length of \(1\) year on mercury?
1. \(172\) earth days
2. \(124\) earth days
3. \(88\) earth days
4. \(225\) earth days
Subtopic:  Kepler's Laws |
 57%
Level 3: 35%-60%
NEET - 2025
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Two planets orbit a star in circular paths with radii \(R\) and \(4R,\) respectively. At a specific time, the two planets and the star are aligned in a straight line. If the orbital period of the planet closest to the star is \(T,\) what is the minimum time after which the star and the planets will again be aligned in a straight line?

1. \((4)^2T\) 2. \((4)^{\frac13}T\)
3. \(2T\) 4. \(8T\)
Subtopic:  Kepler's Laws |
 66%
Level 2: 60%+
NEET - 2022
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The time period of a geostationary satellite is \(24~\text{hr}\) 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. \(6\sqrt{2}~\text{hr}\) 2. \(12\sqrt{2}~\text{hr}\)
3. \(\frac{24}{2.5}~\text{hr}\) 4. \(\frac{12}{2.5}~\text{hr}\)
Subtopic:  Kepler's Laws |
 68%
Level 2: 60%+
NEET - 2019
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