JEE Mains · Physics · STD 11 - Gravitation
- JEE Mains 2021
- Hard
- Numerical
In the reported figure of earth, the value of acceleration due to gravity is same at point \(A\) and \(C\) but it is smaller than that of its value at point \(B\) (surface of the earth). The value of OA \(: AB\) will be \(x : y .\) The value of \(x\) is \(\ldots \ldots \ldots\)

Pick an option to check your answer.
Answer & Solution
Correct Answer
(C) \(4\)
Step-by-step Solution
Detailed explanation
\(g_{A}=\frac{G M(r)}{R^{3}}\)
\(g_{c}=\frac{G M}{\left(R+\frac{R}{2}\right)^{2}}\)
\(g_{A}=g_{C}\)
\(\frac{ r }{ R ^{3}}=\frac{1}{\frac{9}{4} R ^{2}} \Rightarrow r =\frac{4 R }{9}\)
so \(OA =\frac{4 R }{9} ; AB = R - r =\frac{5 R }{9}\)
\(OA : AB =4: 5\)
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