Monday, March 22, 2010

Irodov Problem 3.19























The electric flux through the circle is given by,



Where E is the electric field and dS is the area vector through which E passes. From problem 3.14 we already know that E is given by,



Consider an infinitesimally thin ring section of radius r and width dr. The area vector of this infinitesimally thin ring section is given by,



Hence the flux is given by,

8 comments:

  1. SIR, HOW CAN YOU CONSIDER RING WITH SMALL CROSS SECTIONS IF IT WOULD HAVE BEEN DISC YOU WOULD HAVE CONSIDERED BUT IT IS NOT A DISC

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    1. Question is trying to ask how much flux is passing thru circle area ... Not thru any disk/any other body so dont misunderstand...!. Its just asking how many electric lines of force are passing thru circle area.( just like amount of water which passes thru a similar ring when you keep it in front of shower perpendicular to water flow) . Hope i helped !

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    2. Ayush ur reply was not understandable to me.

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    3. But field lines are virtual.

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  2. Sir there is clearly mentioned that given aera is cricle of radius r.
    Not a disk

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  3. to those who are confused about circle and disc. read the last line of question it asks flus through circle area now as area is mentioned we can consider it as a disc

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