Why is Neutrality Important in Electrostatics of Conductors with Cavities?

[vibhu_baronia]

Homework Statement

when a conductor under electrostatic equlibrium with cavity has charge inside,we say -ve charge is induced at inner surface
by Gauss Law,but why do we say +ve charge induced at surface , I mean thru Gauss Law we
we say Electric field has been canceled out ,why the hell need of neutrality ??

Homework Equations

The Attempt at a Solution

 

[tiny-tim]

welcome to pf!

hi vibhu_baronia! welcome to pf!

when a conductor under electrostatic equlibrium with cavity has charge inside,we say -ve charge is induced at inner surface by Gauss Law,but why do we say +ve charge induced at surface …

charge doesn't come from nowhere

if the conductor starts neutral, then it has to stay neutral …

if a charge is attracted to the inner surface, it leaves an equal and opposite charge behind it!

 

[vibhu_baronia]

Homework Statement

when a conductor under electrostatic equlibrium with cavity has charge inside,we say -ve charge is induced at inner surface
by gauss law,but why do we say +ve charge induced at surface , i mean thru gauss law we
we say electric field has been canceled out ,why the hell need of neutrality ??

Homework Equations

The Attempt at a Solution

thanks a lot !