# A satellite of mass m is orbiting the earth at a height 'h' from its surface. If M is Mass of the earth and R its radius then how much energy must be spent to pull the satellite out of the earth's gravitational field?

$(a)\;\frac{2GmM}{(R+h)^2} \quad (b)\;\frac{GmM}{2(R+h)^2} \quad (c)\;\frac{2GmM}{(R+h)}\quad (d)\;\frac{GmM}{2(R+h)}$

Energy required to remove the satellite from its orbit to infinity is called Binding Energy of the system
Binding energy $=-E=\large\frac{GMm}{2r}$
$\qquad= \large\frac{GMm}{2(R+h)}$
hence d is the correct answer.

edited Feb 17, 2014 by meena.p