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# Physics/magnetism

Question
if a bar magnet of magnetic moment M be bent to a semicircular magnet of radius R, then what will be its magnetic moment?

Hello soumitra,

The general formula for magnetic moment of a semicircular magnet (interpreting semicircular as any fraction of a circle) is
M1 = [2*M*sin(theta/2)] / theta
where theta is in radians. If the semicircle is 180 degrees of arc, or pi radians of arc, that formula reduces to
M1 = 2*M/pi

References:
http://www.gocbse.com/posts/show/0/content-class-12-magnetism-effects-of-current
8.c in section titled MAGNETIC MOMENT

http://sakshieducation.com/(S(limtrz554vycxn45ot2cg2jg))/Inter(New)/Material/IIndYearEM/Physics/04_1_Coulombs_Law.pdf
3. in section titled Unsolved Problem

I hope this helps,
Steve

Physics

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#### Steve Johnson

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I would be delighted to help with questions up through the first year of college Physics. Particularly Electricity, Electronics and Newtonian Mechanics (motion, acceleration etc.). I decline questions on relativity and Atomic Physics. I also could discuss the Space Shuttle and space flight in general.

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I have a BS in Physics and an MS in Electrical Engineering. I am retired now. My professional career was in Electrical Engineering with considerable time spent working with accelerometers, gyroscopes and flight dynamics (Physics related topics) while working on the Space Shuttle. I gave formal classroom lessons to technical co-workers periodically over a several year period.

Education/Credentials
BS Physics, North Dakota State University
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