Let V and E be the gravitational potential and gravitational field at a distance r from the centre of a uniform spherical shell. Consider the following two statements :
(A) The plot of V against r is discontinuous.
(B) The plot of E against r is discontinuous.
(a) Both A and B are Correct.
(b) A is correct but B is wrong.
(c) B is correct but A is wrong.
(d) Both A and B are wrong.
(c) B is correct but A is wrong.
EXPLANATION:
(A) is not correct because the gravitational potential inside the shell is constant =-GM/a, where a is the radius of the shell. As the distance increases from a, the potential gradually starts increasing till infinity to a value zero. So the curve is not discontinuous. (B) is correct because the gravitational field inside the shell is zero and just as it goes outside the value jumps to GM/a² and then gradually decreases to zero at infinity. So the curve at r =a is discontinuous.