multi correct;
in non uniform spherical shell of mass 'm' and radius R (here E is gravitational intensity) which of the following are wrong;
(A) E = 0 (r<R)
(B) ∫ E.dS = 0 on any closed surface inside the shell
(C) E can not be zero at any point inside the shell
(D) Gravitational potential is zero at any point inside the shell.
21a)True.Gravitational field inside any hollow mass=0.
b)True.As E=0.
c)false.From a.
d)false.Gravitational Potential will be equal to that on the surface(which is not 0).
Ans:C),D)
71Since, the charge distribution is non uniform , you cannot say for sure that E is zero inside the shell (If it uniform then even you can't. You can just add that E is zero at center), rather you would say the Flux of Electric field is zero.
hence B is True.
Also, there must exist some point(We don't about it) where the E should be zero.
21The gravitational field(due to the shell) inside(anywhere) inside a symmetric shell=0.
This is not valid for non-symetric objects.
Taking an example,we can consider almost total mass concentrated at a pt. and the ∂m mass forming rest of shell.Here E=0 everywhere.
This difference(from conductors) is shown because of the fact that mass unlike elec. cant move.This is also responsible for the fact that gravitation shielding doesn't exist.
71Oops. I thought that E = Electric field. My answer was presumably for that only.
I would go with C,D then.
