A geo-stationary satellite orbits around the earth in a circular orbit of radius 36000 km. Then, the time period of a spy satellite orbiting a few hundred kilometers above the earth's surface (R_("Earth") = 6400 " km")` will approximately be

Options

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

Answer

C

Explanation

`T^(2)propR` with `R_(e)=6400km`
`(T^(2))/((24)^(2))=((6400)/(36000))^(3)impliesTapprox1.7hr`
For spy satellite R is slightly greater than
`R_(e)impliesT_(S) gt T therefore T_(S)=2hr`