I understand that in electrostatic shielding net charge present inside the cavity and the charge induced around it produce no net electric field in the outside region. Is this also valid for electric potential outside the region?
1 Answer
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You are correct! Here is complete reasoning.
If a charge $Q$ is placed inside cavity, opposite charges are induced on inner surface of cavity (let us call in $Q_{inner}$. Electric field of $Q+Q_{inner}$ does not extend outside cavity.
This means if we we bring a charge from infinity to a point outside cavity, it will never experience a field due to $Q+Q_{inner}$. So potential due to them will be zero.
However we need to be careful about one point. Due to conservation of charges, $Q_{outer}$ will appear on outer surface of conductor. Electric field due to $Q_{outer}$ is present outside and that may cause potential.
