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JEE Main 20238 AprilEvening Shift
Exam
JEE Main
Year
2023
Date
8 April
Shift
Evening Shift
Subject
Physics
Chapter
Gravitation

JEE Main 2023 · 8 April · Evening Shift · Physics · Gravitation

The orbital angular momentum of a satellite is L , when it is...

The orbital angular momentum of a satellite is LL, when it is revolving in a circular orbit at height hh from earth surface. If the distance of satellite from the earth centre is increased by eight times to its initial value, then the new angular momentum will be

Options

  1. A8L8L
  2. B9L9L
  3. C4L4L
  4. D3L3L

Correct answer

D. 3L3L

Step-by-step solution

For a satellite revolving around the Earth in a circular orbit, it can be written that

mv2r=GMmr2...\dfrac{m{v}^{2}}{r} = \dfrac{GMm}{{r}^{2}} . . .\left(1\right)((r = R + histhedistancefromthecentreoftheEarth)</p><p>Simplifyequation(1)toobtainthelinearspeedofthesatellite.</p><p>is the distance from the centre of the Earth)</p><p>Simplify equation (1) to obtain the linear speed of the satellite.</p><p>v = \sqrt{\dfrac{GM}{r}}</p><p>Thus,theangularmomentumofthesatelliteisgivenby</p><p></p><p>Thus, the angular momentum of the satellite is given by</p><p>\begin{cases}L & = & mvr \\ & = & mr\sqrt{\dfrac{GM}{r}} \\ & = & m\sqrt{GMr} . . . \left(2\right)\end{cases}</p><p>Similarly,fordistance</p><p>Similarly, for distancer 'fromthecentreoftheEarth,theangularmomentumisgivenby</p><p>from the centre of the Earth, the angular momentum is given by</p><p>L ' = m\sqrt{GMr '} . . . \left(3\right)</p><p>Divideequation(3)byequation(2)toobtaintherequiredangularmomentum.</p><p></p><p>Divide equation (3) by equation (2) to obtain the required angular momentum.</p><p>\begin{cases}\dfrac{L '}{L} & = & \dfrac{m\sqrt{GMr '}}{m\sqrt{GMr}} \\ & = & \sqrt{\dfrac{r '}{r}} . . . \left(4\right)\end{cases}</p><p>Now,</p><p>Now,{r}^{'} = r + 8r = 9r</p><p>Substitutetheknownvaluesoftheparametersintoequation(4)toobtaintherequiredangularmomentum.</p><p></p><p>Substitute the known values of the parameters into equation (4) to obtain the required angular momentum.</p><p>\begin{cases}\dfrac{L '}{L} & = & \sqrt{9} \\ & ⇒ & L ' = 3L\end{cases}

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