Is There Flux Through the Lateral Surface of a Cylinder?

Click For Summary

Homework Help Overview

The discussion revolves around the concept of electric flux through the lateral surface of a cylinder, particularly in the context of a Gaussian surface. Participants are examining the conditions under which flux may be present and the relevant areas involved in the calculations.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants question the correctness of area expressions used in flux calculations and discuss which surfaces of the cylinder contribute to nonzero flux. There is an exploration of the appropriate formulas for different areas of the cylinder.

Discussion Status

Some participants have provided guidance on the areas to consider for flux calculations, while others are clarifying the definitions and implications of the lateral surface area versus the end surfaces of the cylinder. Multiple interpretations of the problem are being explored, particularly regarding the presence of flux through different surfaces.

Contextual Notes

There is an ongoing discussion about the specific areas relevant to the problem, with some participants noting potential confusion regarding the formulas and assumptions being applied. The original poster's calculations and assumptions are under scrutiny, particularly concerning the lateral surface area of the cylinder.

Fatima Hasan
Messages
315
Reaction score
14

Homework Statement


screenshot_7.png


Homework Equations


screenshot_10.png


The Attempt at a Solution


Here's my work :
screenshot_9.png
 

Attachments

  • screenshot_7.png
    screenshot_7.png
    39.9 KB · Views: 1,308
  • screenshot_10.png
    screenshot_10.png
    2.5 KB · Views: 1,297
  • screenshot_9.png
    screenshot_9.png
    12.2 KB · Views: 1,313
Physics news on Phys.org
Your expressions for the areas don't look correct. When calculating ##\Phi_0##, what particular area are you working with? What is the formula for this particular area ?
 
  • Like
Likes   Reactions: Fatima Hasan
TSny said:
Your expressions for the areas don't look correct. When calculating ##\Phi_0##, what particular area are you working with? What is the formula for this particular area ?
screenshot_14.png
 

Attachments

  • screenshot_14.png
    screenshot_14.png
    9.3 KB · Views: 788
Last edited:
Which parts of the surface of the cylinder have nonzero flux?
 
  • Like
Likes   Reactions: Fatima Hasan
TSny said:
Which parts of the surface of the cylinder have nonzero flux?
The area that we're concerned will be the surface area of the ends of Gaussian surface which is equals to π / R^2
Φ = E A = Q enclosed / ε
Q enclosed = ## 100 * π * (0.1)^2 * 8.85 = 27.8 pC ##
 
Last edited:
Fatima Hasan said:
The area that we're concerned will be the surface area of the ends of Gaussian surface which is equals to π / R^2
Of course you mean π⋅R^2.
Φ = E A = Q enclosed / ε
Q enclosed = 100 * π * (0.1)^2 * 8.85 = 27.8 pC
This is correct.
 
  • Like
Likes   Reactions: Fatima Hasan
TSny said:
Of course you mean π⋅R^2.
This is correct.
##A = 2 \pi r h## , we use this formula to find the net flux through a cylinder , right ?
 
Last edited:
Fatima Hasan said:
##A = 2 \pi r h## , we use this formula to find the net flux through a cylinder , right ?
Not in this problem. The area ##A = 2 \pi r h## is the "lateral" area of the curved surface of the cylinder, as shown below in blue
upload_2018-3-3_14-55-27.png


Is there any flux through the blue surface in the problem you are working on?
 

Attachments

  • upload_2018-3-3_14-55-27.png
    upload_2018-3-3_14-55-27.png
    1.5 KB · Views: 988
  • Like
Likes   Reactions: Fatima Hasan
TSny said:
Not in this problem. The area ##A = 2 \pi r h## is the "lateral" area of the curved surface of the cylinder, as shown below in blue
View attachment 221399

Is there any flux through the blue surface in the problem you are working on?
No
 

Similar threads

Replies
7
Views
2K
Replies
26
Views
2K
  • · Replies 16 ·
Replies
16
Views
1K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 7 ·
Replies
7
Views
4K
  • · Replies 14 ·
Replies
14
Views
1K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 10 ·
Replies
10
Views
1K
  • · Replies 10 ·
Replies
10
Views
11K