- #71
ehild
Homework Helper
- 15,542
- 1,917
You have two concentric shells. The pink regions are conductors, the electric field in a conductor is zero.
The empty spaces are voids, there are electric fields inside them, except the central part enclosed by the small shell.
The geometry has spherical symmetry, so is the symmetry of the field.
The charge on the shells can move and redistributed, but no charge can leave any of the shells.
Consider a Gaussian sphere inside the innermost void. There are no charge enclosed, the field is zero.
Consider a concentric sphere inside the first pink region. The electric field must be zero, so that Gaussian sphere does not enclose any charge. There is no charge inside the conductor or on the inner surface of the shell.
Consider a sphere just outside the first shell. How much charge does it enclose? What is the electric field at radius r in the region between the shells?
Consider a sphere inside the outer pink region. It is conductor, the field is zero. How much is the enclosed charge then?
This sphere encloses the small shell and the inner surface of the big shell. How much is the charge that compensates the charge of the inner shell?
Where can this excess charge be distributed? It can not be inside the metal. It can not leave the shell. Where is it?
If there is some charge on the inner surface of the big shell, how much is on the outer surface?
The empty spaces are voids, there are electric fields inside them, except the central part enclosed by the small shell.
The geometry has spherical symmetry, so is the symmetry of the field.
The charge on the shells can move and redistributed, but no charge can leave any of the shells.
Consider a Gaussian sphere inside the innermost void. There are no charge enclosed, the field is zero.
Consider a concentric sphere inside the first pink region. The electric field must be zero, so that Gaussian sphere does not enclose any charge. There is no charge inside the conductor or on the inner surface of the shell.
Consider a sphere just outside the first shell. How much charge does it enclose? What is the electric field at radius r in the region between the shells?
Consider a sphere inside the outer pink region. It is conductor, the field is zero. How much is the enclosed charge then?
This sphere encloses the small shell and the inner surface of the big shell. How much is the charge that compensates the charge of the inner shell?
Where can this excess charge be distributed? It can not be inside the metal. It can not leave the shell. Where is it?
If there is some charge on the inner surface of the big shell, how much is on the outer surface?
