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JEE Main 201911 JanuaryEvening Shift
Exam
JEE Main
Year
2019
Date
11 January
Shift
Evening Shift
Subject
Physics
Chapter
Gravitation

JEE Main 2019 · 11 January · Evening Shift · Physics · Gravitation

The mass and the diameter of a planet are three times the...

The mass and the diameter of a planet are three times the respective values for the Earth. The period of oscillation of a simple pendulum on the Earth is 2 s2 \mathrm{~s}. The period of oscillation of the same pendulum on the planet would be:

Options

  1. A32 s\frac{\sqrt{3}}{2} \mathrm{~s}
  2. B23 s\frac{2}{\sqrt{3}} \mathrm{~s}
  3. C32s\frac{3}{2} s
  4. D232 \sqrt{3} s

Correct answer

D. 232 \sqrt{3} s

Step-by-step solution

Acceleration due to gravity g=GMR2\mathrm{g}=\frac{\mathrm{GM}}{\mathrm{R}^{2}} gpge=MpMe\frac{g_{p}}{g_{e}}=\frac{M_{p}}{M_{e}}\left(\frac{R_{e}}{R_{p}}\right)^{2}=3(13)2=13\left(\frac{1}{3}\right)^{2}=\frac{1}{3} Also T∝1g⇒TpTe=gegp=3\mathrm{T} \propto \frac{1}{\sqrt{\mathrm{g}}} \Rightarrow \frac{\mathrm{T}_{\mathrm{p}}}{\mathrm{T}_{\mathrm{e}}}=\sqrt{\frac{\mathrm{g}_{\mathrm{e}}}{\mathrm{g}_{\mathrm{p}}}}=\sqrt{3} ⇒Tp=23 s\Rightarrow \mathrm{T}_{\mathrm{p}}=2 \sqrt{3} \mathrm{~s}
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