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. `1/2h`
B. `1h`
C. `2h`
D. `h`

Answer

C

Explanation

`T^(2)propR^(3)`
`T^(2)=KR^(3)implies(24)^(2)=K(36000)^(3)`
`K=1/(9xx10^(4)sqrt10)`
`T'=1/(9x10^(4)sqrt10)(6400)^(3/2)=2h`