Question

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 above the earth's surface ($R_e$ = 6400 km) will approximately be

• A. 1/2 h
• B. 1 h
• C. 2 h
• D. 4 h

Answer 1

The correct option is C

2 h

Time period of a satellite very close to earth's surface is 84.6 min. Time period increases as the distance of the satellite from the surface of earth increase. So, time period of spy satellite orbiting a few hundred km above the earth's surface should be slightly greater than 84.6 min. Therefore, the more appropriate option is (c) or 2 h