JEE MainPhysicsGravitationMCQ+4 / −1
The energy required to take a satellite to a height 'h' above Earth surface (radius of Earth = 6.4 103 km) is E1 and kinetic energy required for the satellite to be in a circular orbit at this height is E2. The value of h for which E1 and E2 are equal, is
- A1.6 103 km
- B3.2 103 km
- C6.4 103 km
- D1.28 104 km
View written solutionFree
Correct answer: B
-
Given
- Radius of Earth:
- Satellite is taken to height above Earth, so orbital radius is
-
Energy required to take the satellite from Earth surface to height
The increase in gravitational potential energy is
-
Kinetic energy of satellite in circular orbit at radius
For circular orbit,
Hence kinetic energy is
-
Condition given:
So,
Cancel :
Rearranging,
Therefore,
-
Find height
Since we get
Now substitute :
-
Option check
- A: km ✗
- B: km ✓
- C: km ✗
- D: km ✗
Therefore, the correct answer is Option B.
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