How Do You Solve This Capacitor Problem with Aluminum Electrodes?

  • Thread starter Thread starter RED119
  • Start date Start date
  • Tags Tags
    Capacitor
Click For Summary
The problem involves calculating the capacitance of two aluminum electrodes with a diameter of 5.0 cm and a separation of 0.50 mm, connected to a 200 V battery. The capacitance formula C = εA/d was applied, with the area calculated as π * (d^2/4). The user obtained a capacitance of 139 pF, but the online homework platform indicated this result was incorrect. The discussion highlights a potential error in the area calculation, suggesting a review of the formula used for the area of the electrodes. Accurate calculations are crucial for determining the correct capacitance value.
RED119
Messages
29
Reaction score
3

Homework Statement


Two 5.0-cm-diameter aluminum electrodes are spaced 0.50 mm apart. The electrodes are connected to a 200 V battery.

Homework Equations


C = εA/d

The Attempt at a Solution


So for my solution I took the area of the plate, ((.052π) * 8.85*10-12) / .5*10-3 and I got an answer of 1.39 * 10-10 F or 139 pF. The website the homework is done through is saying this is wrong. not too sure where the mistake is...
 
Physics news on Phys.org
Area of electrode = pi * d^2 /4

Looks like you used pi * d^2
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

Similar threads

  • · Replies 2 ·
Replies
2
Views
5K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 1 ·
Replies
1
Views
7K
  • · Replies 2 ·
Replies
2
Views
1K
Replies
4
Views
2K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 2 ·
Replies
2
Views
5K
  • · Replies 2 ·
Replies
2
Views
6K
  • · Replies 5 ·
Replies
5
Views
4K