# Homework Help: Ring of charge electric potential

1. Feb 4, 2014

### Panphobia

1. The problem statement, all variables and given/known data
The ring is in the z,y plane.
D = 2m
R = 4m
Q = 8 * 10^-6 C
X = distance to the edge
λ = dQ/dX
dX = rdθ
dQ = infinitely small charge
dX = infinitely small arc of ring

What is the potential difference at the point D perpendicular to the centre of the ring?

2. Relevant equations
$\int \frac{kdQ}{X}$

3. The attempt at a solution

$\int \frac{kλrdθ}{(D^2+R^2)^{1/2}}$
After this how do I get it in terms of dθ?

Last edited: Feb 4, 2014
2. Feb 4, 2014

### Tanya Sharma

What is the question ? Are you required to find the potential of the ring at a point 2m away from the center ,and lying on the axis of the ring ?

3. Feb 4, 2014

### Panphobia

Yea I gave the question after all the variables were specified

4. Feb 4, 2014

### Tanya Sharma

What is the problem ? Just integrate the expression with appropriate limits.The variable of integration is θ .

5. Feb 4, 2014

Thats it?

6. Feb 4, 2014

### Tanya Sharma

What does that mean ?

7. Feb 4, 2014

### Panphobia

So what are we integrating to 0 to 2pi?

8. Feb 4, 2014

### Tanya Sharma

Yes... the range of θ is 0 to 2pi .