13. A spherical metal shell A of radius RA and a solid
metal sphere B of radius Ro(< RA) are kept far
apart and each is given charge '+Q'. Now they
are connected by a thin metal wire. Then
(1) EN
inside
= 0
(2) QA > Qg
OA_Ro
(3)
(4) EN
on surface
A
<EM
on surface
B
OB
Answers
Answered by
1
Answer:
ANSWER
The potential for both the objecs is same so,
R
A
KQ
A
=
R
B
KQ
B
or
Q
B
Q
A
=
R
B
R
A
As R
B
<R
A
we get Q
A
>Q
B
Above equation represents B is correct option.
From Gauss law the electric field inside a spherical shell is zero so option A is correct.
Now σ
A
=
4πR
A
2
Q
A
and σ
B
=
4πR
B
2
Q
B
Thus
σ
B
σ
A
=
Q
B
Q
A
×(
R
A
R
B
)
2
=
R
B
R
A
×(
R
A
R
B
)
2
=
R
A
R
B
Thus option C is also correct.
Electric fields on the surface of shell and sphere are
E
A
=
ϵ
o
σ
A
and
E
B
=
ϵ
o
σ
B
Thus
E
B
E
A
=
σ
B
σ
A
<1
or
E
A
<E
B
So option D is also correct.
October 15, 2019
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