# Doubt from electrostatics

#1

In this question shouldn't the answer be A,C and D? As inner charge cannot produce an effect at P as it's electric field cannot pass through the conductor ?

Also another question

How to solve this ?

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#2

At inner surface charge gets distributed non uniformly (As +q not placed at center of cavity and cavity itself is not symmetrical).
This inner surface charge distribution plus the +q makes electric field zero outside the inner surface .(At any point in the space).
Thus we get answer B.

Charge gets uniformly distributed on outer surface of sphere(In order to make electric field due to this zero inside the sphere which is CONDUCTOR)
Now electric field due to outer surface is option c)(By gauss law)

#3

Inner charge (+q)produce a effect at P but that electric field is cancelled by the inner surface charge distribution(-q).
It doesn’t mean they don’t produce electric field individually.Only the net electric field caused by these two gets cancelled.

#4

Thanks, I had the misconception that electric field of cavity will never goto any exterior point.

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#5

Griffith explanation...

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#6
#7
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#8