JEE Mains · Physics · STD 11 - Gravitation
- JEE Mains 2021
- Hard
- MCQ
Two satellites \(A\) and \(B\) of masses \(200\, kg\) and \(400\, kg\) are revolving round the earth at height of \(600\, km\) and \(1600\, km\) respectively. If \(T _{ A }\) and \(T _{ B }\) are the time periods of \(A\) and \(B\) respectively then the value of \(T _{ B }- T _{ A }\) [Given : radius of earth \(=6400\, km\), mass of earth \(=6 \times 10^{24}\, kg\) ]

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Answer & Solution
Correct Answer
(A) \(1.33 \times 10^{3} s\)
Step-by-step Solution
Detailed explanation
\(T =2 \pi \sqrt{\frac{ r ^{3}}{ GM }}\)
\(T _{ A }=2 \pi \sqrt{\frac{(6400+600) \times 10^{3}}{ GM }}\)
\(T _{ A }=2 \pi \times 10^{9} \sqrt{\frac{7^{3}}{ GM }}\)
\(T _{ B }=2 \pi \times 10^{9} \sqrt{\frac{8^{3}}{ GM }}\)
\(T _{ B }- T _{ A }=\frac{2 \pi 10^{9}}{\sqrt{ GM }}[8 \sqrt{8}-7 \sqrt{7}]\)
\(=314 \times 4.107\)
\(=1289.64\)
\(=1.289 \times 10^{3} s\)
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