A geostationary satellite orbits around the earth in a circular orbit of radius 36,000 km. then the time period of a spy satellite orbiting a few hundred km (600 km) above the earth's surface (R=6400 km) will approximately be

Options

A. `(1)/(2)h`
B. 1h
C. 2h
D. 4h

Answer

C

Explanation

Let the time priod at earth's surface = T
For geo - stationary satellite, `T_(2) = 24` hour,
`R_(2)=36,000 km`
For spy satellite, `T_(1) = ? R_(1) ~~ 6400 km`
`therefore ((24)/(T_(1)))^(2) = ((36000)/(6400))^(3)` or `T_(1) = (24)/(13.34) = 1.8h`