Question

The time period of revolution of geostationary satellite with respect to earth is
A. 24 hrs
B. 1 year
C. infinity
D. zero

Answer 1

The time taken by a satellite to revolve around earth depends on the fact that how the satellite is revolving around earth. The relative motion between earth and the satellite decides the time period of the satellite with respect to earth.

Complete step by step answer:
Objects that revolve around earth in a fixed circular orbit are known satellites. Moon is earth’s natural satellite but there are many man made satellites put into orbit around earth. They are called artificial satellites. There are two types of artificial satellites: Polar satellites and geo-stationary satellites. This classification is based on the type of orbit around earth.

Geo-stationary satellites are those satellites which revolve along the equator of earth. This means that the time taken by them to complete a revolution is equal to the time taken by earth to complete one rotation which is equal to 1 day or 24 hours. But option A is not the right answer to this question which is asking the time period with respect to earth. Since there is no relative motion between earth and the geostationary satellite, they seem to have time period equal to infinity.
Hence, the correct answer is option C.

Additional Information
Polar Satellites are those satellites which revolve around Earth moving from one pole to the other pole. Due to this type of motion, their orbit is perpendicular to the line of equator of Earth. Their movement is from North to South direction while Earth revolves from east to west.

They orbit at lower altitudes and are closer to the surface of Earth. Their time period of revolution is around 100 minutes. The period of revolution is short due to which the satellite crosses the same point on Earth many times a day.

Note:
The geostationary satellites are called so because they revolve around the earth moving along the equator with the same speed as earth. This makes them appear to be stationary in the sky to an observer looking at them from earth.