Two particles of masses 'm' and '9m' are separated by a distance 'r'. At a point on the line joining them the gravitational field is zero. The gravitational potential at that point is (G = Universal constant of gravitation)
1
\( - \dfrac{4 Gm}{r} \)
2
\( - \dfrac{8 Gm}{r} \)
3
\( - \dfrac{16 Gm}{r} \)
4
\( - \dfrac{32 Gm}{r} \)
5
\( - \dfrac{18 Gm}{r} \)