Confusion to the solution of a MIT ocw problem

In summary, the conversation is about a broken snipping tool and a question regarding problem 1.6 on a physics assignment. The equations involved are E_{sheet}=\frac{σ}{2ε_{0}}, E_{slab}=\frac{ρD}{2ε_{0}}, and \frac{Q}{ε_{0}}=\ointEdA. The person asking the question is confused about the positive and negative signs for regions I, II, and III on the Esheet and seeks clarification. Another person suggests considering the problem from a flux perspective and mentions using 3 equations and 3 unknowns.
  • #1
JYangQi00
2
0

Homework Statement


My snipping tool is totally broken. So I'm going to leave a link :x
It's problem 1.6
http://ocw.mit.edu/courses/physics/8-02-electricity-and-magnetism-spring-2002/assignments/ps1a.pdf

Homework Equations



[itex]E_{sheet}[/itex]=[itex]\frac{σ}{2ε_{0}}[/itex]
[itex]E_{slab}[/itex]=[itex]\frac{ρD}{2ε_{0}}[/itex]
[itex]\frac{Q}{ε_{0}}[/itex]=[itex]\oint[/itex]EdA

The Attempt at a Solution



I got everything on the solutions page (http://ocw.mit.edu/courses/physics/8-02-electricity-and-magnetism-spring-2002/assignments/pss1.pdf) But I can't seem to understand why region I of Esheet is positive and Regions II and III are negative. If σ is a negative charge, shouldn't the signs be switched around?
 
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  • #2
It's interesting that you have Gauss's Law as one of your equations. When taking a look at the plane, have you thought about it from a flux perspective?
 
  • #3
JYangQi00 said:

Homework Statement


My snipping tool is totally broken. So I'm going to leave a link :x
It's problem 1.6
http://ocw.mit.edu/courses/physics/8-02-electricity-and-magnetism-spring-2002/assignments/ps1a.pdf

Homework Equations



[itex]E_{sheet}[/itex]=[itex]\frac{σ}{2ε_{0}}[/itex]
[itex]E_{slab}[/itex]=[itex]\frac{ρD}{2ε_{0}}[/itex]
[itex]\frac{Q}{ε_{0}}[/itex]=[itex]\oint[/itex]EdA

The Attempt at a Solution



I got everything on the solutions page (http://ocw.mit.edu/courses/physics/8-02-electricity-and-magnetism-spring-2002/assignments/pss1.pdf) But I can't seem to understand why region I of Esheet is positive and Regions II and III are negative. If σ is a negative charge, shouldn't the signs be switched around?
Welcome to PF !

Here is an image of the problem:

attachment.php?attachmentid=67685&stc=1&d=1394920480.png
 

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  • #4
Post #2 is a good hint, follow it!
3 equations, 3 unknowns, 3 gaussian surfaces.
Hint: make sure two of them line up correctly!
 
  • #5
SammyS said:
Welcome to PF !

Here is an image of the problem:

attachment.php?attachmentid=67685&stc=1&d=1394920480.png

Thanks! My snipping tool makes it so that the screen turns gray and I snip black images >_<
 

FAQ: Confusion to the solution of a MIT ocw problem

1. What is MIT OCW?

MIT OCW (OpenCourseWare) is a free online platform that provides access to educational materials used in undergraduate and graduate-level courses at the Massachusetts Institute of Technology (MIT). These materials include lecture notes, videos, assignments, and exams.

2. What causes confusion when solving an MIT OCW problem?

Confusion when solving an MIT OCW problem can be caused by a variety of factors, such as lack of understanding of the underlying concepts, unclear instructions, or difficulty in applying the learned concepts to the problem at hand.

3. How can I effectively approach solving an MIT OCW problem?

The key to effectively solving an MIT OCW problem is to first make sure you have a thorough understanding of the relevant concepts. Then, carefully read and analyze the problem, breaking it down into smaller, more manageable parts. Finally, use the appropriate methods and techniques to solve each part, and then combine the solutions to arrive at the final answer.

4. Are there any resources available to help with solving MIT OCW problems?

Yes, there are several resources available to help with solving MIT OCW problems. These include online forums, study groups, and tutoring services. Additionally, many OCW courses provide solutions to practice problems and offer office hours or online Q&A sessions with instructors.

5. How can I improve my problem-solving skills when using MIT OCW?

One way to improve problem-solving skills when using MIT OCW is to actively engage with the materials and to practice solving problems regularly. It can also be helpful to seek out feedback from peers or instructors and to reflect on your thought process and approach to solving problems.

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