A particle of mass M is situated at the centre of a spherical shell of same mass and radius a. The magnitude of the gravitational potential at a point sutuated at a/2 distance from the centre, will be :
A
$${{GM} \over a}$$
B
$${{2GM} \over a}$$
C
$${{3GM} \over a}$$
D
$${{4GM} \over a}$$
2
AIPMT 2011 Mains
MCQ (Single Correct Answer)
+4
-1
A particle of mass m is thrown upwards from the surface of the earth, with a velocity u. The mass and the radius of the earth are, respectively, M and R. G is gravitational constant and g is acceleration due to gravity on the surface of the earth. The minimum value of u so that the particle does not return back to earth, is
A
$$\sqrt {{{2GM} \over {{R^2}}}} $$
B
$$\sqrt {{{2GM} \over R}} $$
C
$$\sqrt {{{2gM} \over {{R^2}}}} $$
D
$$\sqrt {2g{R^2}} $$
3
AIPMT 2011 Prelims
MCQ (Single Correct Answer)
+4
-1
A planet moving along an elliptical orbit is closest to the sun at a distance r1 and farthest away at a distance of r2. If $$v$$1 and $$v$$2 are the linear velocities at these points respectively, then the ratio $${{{v_1}} \over {{v_2}}}$$ is
A
(r1 /r2)2
B
r2/r1
C
(r2/r1)2
D
r1/r2
4
AIPMT 2010 Mains
MCQ (Single Correct Answer)
+4
-1
The dependence of acceleration due to gravity g on the distance r from the centre of the earth, assumed to be a sphere of radius R of uniform density is as shown in figures below
