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7. gravitation — Physics STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 SciencePhysics7. gravitation1 Mark
MCQ
The time period of a satellite revolving around earth in a given orbit is $7 \,hours$. If the radius of orbit is increased to three times its previous value, then approximate new time period of the satellite will be ...... $hours$
  • A
    $40$
  • ✓
    $36$
  • C
    $30$
  • D
    $25$
✓

Answer

Correct option: B.
$36$
b
$T =\frac{2 \pi}{\sqrt{ GM }} r ^{3 / 2}$

$\frac{ T _{1}}{ T _{2}}=\left(\frac{ r _{1}}{ r _{2}}\right)^{3 / 2}=\left(\frac{1}{3}\right)^{3 / 2}$

$T _{2}= T _{1} 3 \sqrt{3}=21 \sqrt{3} \,\text { hours }$

$\approx 36 \,\text { hours }$

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