Need suggestion on an MIT OCW material

AI Thread Summary
The discussion centers on a query regarding the upper limit of integration over "r" being infinity in MIT's course material on electric fields. The original poster mistakenly referenced the wrong page, while another participant clarified that the relevant page is likely page 63, where the total charge is calculated. The need for an infinite limit arises because the charge distribution extends infinitely in all directions. Additionally, there was a technical issue with the link provided, which was corrected. The thread was also moved to the appropriate section for better visibility.
kamaljit
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Hi i would be glad if someone can help me on this.
I am having a bit of trouble in understanding why the upper limit of integration over "r" is infinity in the MIT open course material on Electric field page #16 by Prof Markus Zahn (material attached as a link to the pdf). Please help.

Thanks in advance.
Link to MIT oc material:
http://ocw.mit.edu/resources/res-6-002-electromagnetic-field-theory-a-probl%20em-solving-approach-spring-2008/textbook-contents/chapter2.pdf
 
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Almost impossible to know what you mean when the link doesn't work and page 16 doesn't have any integral in it at all.

I'm guessing you perhaps meant page page 63 where he integrate to get the total charge? In that case the charge distribution extends to infinity (in all directions) so to get the total charge you need to integrate over the entire volume (i.e. infinity).

I also suspect your thread is posted in the wrong section.
 
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Thank you for your quick reply and sorry that 1. the link isn't working (i copied the link correctly but somehow it is not working) and 2. about posting in the wrong section...
 
You got a space in "pro blem" in your link. This should be the correct one
http://ocw.mit.edu/resources/res-6-002-electromagnetic-field-theory-a-problem-solving-approach-spring-2008/textbook-contents/chapter2.pdf
I didn't spot it either at first but I found the course on ocw site.
 
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thank you for this correction.
 
Incand said:
I also suspect your thread is posted in the wrong section.

I've moved it. Cheers!
 
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