When a satellite moves around the earth in a certain orbit, the quantity which remains constant is :

The largest and the shortest distance of the earth from the sun are ${r_1}$ and ${r_2}$, its distance from the sun when it is at the perpendicular to the major axis of the orbit drawn from the sun

Mean solar day is the time interval between two successive noon when sun passes through zenith point (meridian). Sidereal day is the time interval between two successive transit of a distant star through the zenith point (meridian). By drawing appropriate diagram showing the earth's spin and orbital motion, show that mean solar day is $4\,\min$ longer than the sidereal day. In other words, distant stars would rise $4\,\min$ early every successive day

The time period of a geostationary satellite is $24\; \mathrm{h}$, at a helght $6 \mathrm{R}_{\mathrm{E}}( \mathrm{R}_{\mathrm{E}}$ is radius of earth) from surface of earth. The time period of another satellite whose helght is $2.5 \mathrm{R}_{\mathrm{E}}$ from surface will be

A satellite moves round the earth in a circular orbit of radius $R$ making one revolution per day. A second satellite moving in a circular orbit, moves round the earth once in $8$ days. The radius of the orbit of the second satellite is

A planet has orbital radius twice as the earth's orbital radius then the time period of planet is .......... $years$