Question

Rohini satellite at a height of $500 \,km$ and INSAT-B at a height of $3600\, km$ from surface of earth, then relation between their orbital velocity $\left(v_{R}, v_{I}\right)$ is

• A. $\left(v_{R} > v_{I}\right)$
• B. $\left(v_{R}< v_{I}\right)$
• C. $\left(v_{R}=v_{I}\right)$
• D. No relation

Answer 1

Answer: (A)

Orbital velocity of a satellite is given by $v_{o}=\sqrt{\frac{G M_{e}}{r}}$
where $G=$ gravitational constant.
$M_{e}=$ mass of the earth
$r=$ distance of the satellite from the centre of the earth
$\therefore v_{o} \propto \frac{1}{\sqrt{r}}$
As the distance of INSAT-B from the centre of the earth is greater than the distance of Rohini from the centre of the earth
$\therefore v_{R} > v_{I}$