PPSC Excise and Taxation Inspector 2018 Question Paper

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28.

A Geostationary Satellite :

A: revolves about the polar axis
B: has a time period less than that of the near earth satellite
C: move faster than a near earth satellite
D: is stationary in the space

The answer is: A

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Explanation

Answer: A - Revolves about the polar axis

 

Why A is Correct:

  • A geostationary satellite revolves around Earth in the same direction Earth rotates - west to east
  • Since Earth rotates about its polar axis, the satellite also revolves about the polar axis
  • It orbits directly above the equator at ~35,800 km altitude
  • It completes one revolution in exactly 24 hours - matching Earth's rotation
  • This makes its relative velocity with respect to a point on Earth = zero, so it appears stationary
  • Its orbit is called Parking Orbit

 

Why other options are wrong:

B - Time period less than near earth satellite - Wrong. Geostationary period is 24 hours, which is much longer than near-Earth satellites
C - Moves faster than near earth satellite - Wrong. Near-Earth satellites orbit closer and must travel significantly faster to maintain orbit
D - Stationary in space - Wrong. It is never at rest - it constantly revolves. It only appears stationary due to zero relative velocity with Earth's surface

 

Key properties of Geostationary Satellite:

  • Altitude~35,800 km
  • Time period : 24 hours
  • Orbit type :Equatorial, circular
  • Direction : West to East
  • Appears : Stationary from Earth
  • Orbit name : Parking Orbit
  • Uses : Communication, weather forecasting

 

Important satellite facts:

  • First geostationary satellite (World) : Syncom 3 (NASA, 1961)
  • First geostationary satellite (India) : APPLE (Ariane Passenger Payload Experiment)
  • Largest satellite in Solar System : Ganymede (moon of Jupiter)
  • Smallest satellite in Solar System : Phobos (moon of Mars)
  • Planet with most satellites : Jupiter