Gravitation Question 116
Question: A solid sphere of uniform density and radius 4 units is located with its centre at the origin O of coordinates. Two spheres of equal radii 1 unit with their centres at A(? 2, 0, 0) and B(2, 0, 0) respectively are taken out of the solid leaving behind spherical cavities as [IIT 1993]
Options:
A) The gravitational force due to this object at the origin is zero
B) The gravitational force at the point B (2, 0, 0) is zero
C) The gravitational potential is the same at all points of the circle
D) The gravitational potential is the same at all points on the circle
Show Answer
Answer:
Correct Answer: A
Solution:
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Since cavitiesare symmetrical w.r.t. O. So the gravitational force at the centre is zero.
The radius of the circle
is 6. For all points for the body behaves as if whole of the mass is concentrated at the centre. So the gravitational potential is same. Above is true for as well.