# Charge on conductors

In a books Concepts of Physics by HC Verma,It is written that one a conductor only one surface cannot be charged.Both the surfaces have to be charged in order for the net electric field inside the conductor to be zero.I had a doubt regarding this.Suppose a conductor has a positive charge only on one side.Then the positive charge will create an electric field due to which the free electrons inside the conductor will move away from the field.So one side there would be a positive charge and on one side a negative charge.These charges will also create an electric field on a direction opposite to that of the field by the positive charge on the surface.Hence the Net electric field will become zero at some point inside the conductor.So why is A conductor charged only on one side not possible?

• Please elaborate your question. In one part you are saying that ".Then the positive charge will create an electric field due to which the free electrons inside the conductor will move away from the field.So one side there would be a positive charge and on one side a negative charge." and you are asking why charge on only one surface is not possible. Your answer is in your question. Commented Jun 3, 2020 at 4:23
• With only one surface charged the net electric field is still 0.So why is it necesssary for both surfaces charged to create a net electric field Commented Jun 3, 2020 at 4:26
• And can you say the page number where it is written? Commented Jun 3, 2020 at 4:27
• Page 134 Hc Verma Part 2 Commented Jun 3, 2020 at 4:28
• it must have been for an isolated neutral (uncharged) conductor in electric field , when a isolated neutral conductor is placed in an electric field only one surface getting charged is not possible. but if it is not clear can you please provide in which line it is written Commented Jun 3, 2020 at 4:46

Conductors (here) are of two types :

1) Having net charge

2) Not having net charge (*Conductors can have a charge separation without being injected with external charges)

Lets get to the theory why for Electric field inside a conductor(neutral) to be zero, both sides must have charge.

Now lets see what happens if we place a 1 Coloumb Charge inside the conductor.

The negative charges on the left surface and positive charges on the right surface will push the 1C charge towards left.

And the Electric field will push the 1C charge towards right.

Both of these forces cancel each other out and so the net Electric field inside the conductor is 0.

It is not possible to charge only one side of the (*neutral) conducting cube. This is because the moment when a charge develops on one side , due to that charge the opposite charges are repelled to the other sides thus causing charge separation on both sides.

Edit : In the second photo , it should be 'Repelled by $$\color{red}{positive}$$ charge on the right surface'