# Equipotential lines -

1. Jul 20, 2010

### pat666

1. The problem statement, all variables and given/known data

Sketch the equipotential surfaces which result from the following charge configurations:
(a) a point charge
(b) a spherically symmetric charge distribution
(c) a very large, plane, uniformly-charged sheet
(d) a long, uniformly-charged cylinder
(e) an electric dipole.

sorry I have posted this already but i figured since i mainly just need a check id stick it in a different thread.
I am pretty sure that a and e are correct, unsure of b and d and I need some help with c... thanks

2. Relevant equations

3. The attempt at a solution

#### Attached Files:

• ###### equi.jpg
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2. Jul 20, 2010

### Onamor

It might help understanding to think about these in terms of http://hyperphysics.phy-astr.gsu.edu/Hbase/electric/gaulaw.html" [Broken].

B is wrong. D is probably better drawn in 3D if you can. For C, think about the gravitational field right at the surface of the earth - this is a good approximation.

Last edited by a moderator: May 4, 2017
3. Jul 20, 2010

### pat666

sorry but could you give me a bit more of a hand - ive never heard of Gauss' law (excluding the million things in maths he did) D i dont think i can draw in 3d???, b i have no idea what else to do and c i will look at the gravitational field right at the surface of the earth now

4. Jul 20, 2010

### Onamor

What will B look like from a huge distance away? (Think about stars in the sky!!! :rofl:)

D is misleading in 2D. If the marking is really picky it might even be wrong - remember how to draw field lines into and out of a page? to draw in 3D just draw a coke can, then rub out the ends or something!

5. Jul 20, 2010

### pat666

been a year since i did this in high school but i think that x means out of page and dots mean in??

6. Jul 20, 2010

### pat666

is this what you meant for d????? (really dodgy)

#### Attached Files:

• ###### d.png
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7. Jul 20, 2010

### Onamor

Its long, so you can ignore the effects at the ends presumably.

Describe what it should look like. Again, you can picture it from far away.

8. Jul 20, 2010

### pat666

I really cant picture it ay. so for d if I cut off the ends will it be right then?