# Parallel Plate Conductor Question

1. Apr 5, 2013

### Benny851

1. The problem statement, all variables and given/known data
There are 2 parallel plates of unknown area. The area between the 2 plates is completely filled with 150 kg of water. The capacitance is .3 mirofaradays. K of water is 120 and had density of 1000 kg/m^3. Also Eo = 9.1 x 10^-12 C^2/(NxM^2). Determine the distance between the 2 plates.

2. Relevant equations
D=M/V
C= KEo(A/D)

3. The attempt at a solution

Hello all, I think I have listed all of the relevant equations above. From how I see it, I need to find the area of the plates and then simply plug and chug using the above equation. However, I have no idea how to find the area with the information I have been given. Am I on the right track and how do you suggest I go about finding the area?

2. Apr 5, 2013

### Staff: Mentor

I'm not sure what you mean with D - in the first equation, it looks like a density, in the second equation it looks like a distance.

The amount of water allows to find a relation between area and distance, you can use this relation in the formula for the capacitance to solve the problem.

3. Apr 6, 2013

### Benny851

How does amount of water give me a relationship between area and distance? I do not see how the mass of the water can help. it can give me the volume because I am also given the density. But I do not see how even the volume can help me find a relationship between area and distance. Can someone please explain what it is that I am overlooking? Thanks.

4. Apr 6, 2013

### Benny851

Can someone please help me with this problem???

5. Apr 6, 2013

### Staff: Mentor

If you have a box with a floor area of 2m^2 and a height of 1m, can you calculate its volume? Which formula did you use?

6. Apr 6, 2013

### Benny851

yes, I understand area*height = volume, but I do not know either area or volume, so I do not see how that formula can help me. Can you please be a little more straightforward in your responses. I understand you want me to learn it on my own, but time is of the essence.

7. Apr 7, 2013

### novko

If you have an objects mass and density, can you calculate it's volume? What is the relationship between mass and density?

8. Apr 7, 2013

### Staff: Mentor

Don't give up before you even tried. Write down the formula, and try to use it in the other formula.
It will go quicker if you follow my hints.

9. Apr 7, 2013

### ravikannaujiya

from first eqution in you find volume= area*distancebetween the plates
from second equation you can find, area/ distance between the plates
now, you have two unknown and two eqautions, you can find both area of plates and the distance between them.

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