Concept: • Geostationary satellite: It is an earth-orbiting satellite placed at a height of about 36000 km from the earth's surface. A few characteristics of this satellite includes • It revolves in an orbit that is aligned with the equatorial plane of the earth. • It has the same direction of rotation as that of the earth i.e. from west to east. • It rotates with the same angular speed as the earth. • The time period of the satellite: It is the time taken by the satellite to complete one revolution around the Earth. • Consider a satellite orbiting the earth at a height h from the surface of the earth of radius R. • The circumference of orbit of satellite = 2π(R+h) • The orbital velocity of the satellite at a height h is given by, \(⇒ v_0 =\sqrt{\frac{GM}{R+h}}\) Where M is the mass of the Earth. The time period of the satellite is given by: \(⇒ T = \frac{circumference}{orbital \: velocity} = \frac{2\pi(R+h)}{\sqrt{\frac{GM}{R+h}}} = 2\pi\sqrt{\frac{(R+h)^3}{GM}}\) Explanation: • A satellite whose time period is 24 hours and is revolving in an orbit concentric and coplanar with the equatorial plane of earth is called a geostationary satellite. • The geostationary satellite revolves at the height of about 36000 km from the surface of the earth. • The orbital velocity of the geostationary satellite is about 3.08 km/sec