Charge On A Infinite Conductor Slab From An Infinite Sheet Of Charge

In summary, the conversation discusses an infinite sheet of charge with a charge density of -2.1 uc/m2 and an inner edge 2.6 cm away and an outer edge 4.2 cm away. The conductor slab has a charge density of 74 uc/m2. The question is asking for the charge per unit area on the surface of the slab at 4.2 cm. The solution involves considering three sheets of charge and using Gauss's Law to find the correct answer.
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Homework Statement



http://imgur.com/sg8czUR

An infinite sheet of charge has a charge density of σ= -2.1 uc/m2. (uc is micro-coulombs). The inner edge of the infinite conductor slab is 2.6 cm away. The outer edge is 4.2 cm away. The conductor slab has a charge density of σ= 74 uc/m2. What is the charge per unit area on the surface of the slab at 4.2 cm. (The outer edge)

Homework Equations



Gauss's Law!

The Attempt at a Solution



Well we know since the slab is a conductor the charges in it are going to move to make the electric field equal zero every inside of it. I have the inner being 2.1 uc/m2. The total charge of the slab must be 74 uc/m2. Therefore I thought the outer edge will have a charge of 71.9 uc/m2. But this is not the right answer. Any idea of what I am doing wrong here?
 
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If you have 2.1 μC on the left surface of the conductor, the electric fields due to that charge and the sheet of charge will indeed cancel inside the conductor, but you would still have the rest on the charge on the conductor around, which would result in a non-zero field inside the conductor.

Look at it as three sheets of charge: the one through the origin, the one on the left surface of the conductor, and the one on the right surface of the conductor. The fields from the three sheets have to sum to zero inside the conductor.
 
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1. What is the difference between a conductor and an insulator?

A conductor is a material that allows electric charges to move freely through it, while an insulator is a material that does not allow electric charges to move through it easily.

2. How does the charge on an infinite conductor slab differ from that on an infinite sheet of charge?

The charge on an infinite conductor slab is distributed evenly throughout the entire slab, while the charge on an infinite sheet of charge is concentrated on the surface of the sheet.

3. How does the charge on an infinite conductor slab affect the electric field around it?

The charge on an infinite conductor slab creates an electric field that is perpendicular to the surface of the slab and decreases in strength as you move further away from the slab.

4. Can the charge on an infinite conductor slab be changed?

Yes, the charge on an infinite conductor slab can be changed by adding or removing charges from the surface of the slab.

5. How does the distance from the infinite conductor slab affect the electric field strength?

The electric field strength decreases as the distance from the infinite conductor slab increases. This relationship follows an inverse-square law, meaning that the electric field strength is inversely proportional to the square of the distance from the slab.

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