Capacitance of two parallel plate capacitors

  • Thread starter Violagirl
  • Start date
  • #1
Violagirl
114
0

Homework Statement



Two square metal plates with sides of length 0.1 m are separated in vacuum by 10-3 m. Find their capacitance.

Homework Equations



C = Q/V

For a parallel plate capacitor:

C = E0A/L


The Attempt at a Solution



If A is supposed to be the length of the metal plates with 0.1 m, since A has units of m2, I took A = (.1m)2 = .01 m2 and L = 10-3 m.

From there and plugging everything in, I get:

C = (8.85 x 10-12 C2/N m2 * .01m2/10-3 m

C = 8.85 x 10-11 Farads

If someone could confirm whether this is correct or not, I would appreciate it.
 

Answers and Replies

  • #2
NascentOxygen
Staff Emeritus
Science Advisor
9,242
1,073
If A is supposed to be the length of the metal plates with 0.1 m, since A has units of m2, I took A = (.1m)2 = .01 m2 and L = 10-3 m.
A is the area of each plate. (The area of one face of a plate.)
 
  • #3
Violagirl
114
0
Right about A. What I meant was, of the two numerical values that I'm provided, which would be my A? Or how do I determine my A? I know then that my separation distance corresponds to L. So do I need to determine A by my length values in this situation?
 
  • #4
NascentOxygen
Staff Emeritus
Science Advisor
9,242
1,073
A is the area of the square plate. It's 0.1m per side, so A = (0.1m)² as you showed.
 
  • #5
Enigman
665
307

Homework Statement



Two square metal plates with sides of length 0.1 m
This is the dimension of plate.
are separated in vacuum by 10-3 m. Find their capacitance.

This is the distance between the plate
Do not get confused by them. Dimensions of the plate has nothing to do with distance between the plates.

(Also the title is wrong there's only one parallel plate capacitor here, two plates make a capacitor.)
 
  • #6
Violagirl
114
0
This is the dimension of plate.


This is the distance between the plate
Do not get confused by them. Dimensions of the plate has nothing to do with distance between the plates.

(Also the title is wrong there's only one parallel plate capacitor here, two plates make a capacitor.)

Oh shoot! I did not realize that. Do I need to redo this problem then and look at other equations to determine capacitance then?
 
  • #7
Enigman
665
307
Er...no everything is correct; just show how you found area by the dimensions given.
 
  • #8
Violagirl
114
0
Oh got it! Will do, thanks so much for looking at this!
 

Suggested for: Capacitance of two parallel plate capacitors

Replies
0
Views
2K
  • Last Post
Replies
5
Views
2K
  • Last Post
Replies
3
Views
5K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
5
Views
3K
  • Last Post
Replies
2
Views
2K
Replies
2
Views
4K
Replies
3
Views
1K
  • Last Post
Replies
7
Views
14K
Top