111.
F = i*L*B
L = The displacement vector of the starting and ending point
F=iλB
1 . A wire carrying a current i is kept in X-Y plane along the curve y=A sin(2Πx/λ) .A magnetic field B exists in the z-direction.FInd the magnitude of the magnetic force on the portion of the wire between x=0 and x=λ
2.A circular loop of radius a carrying a current i is placed in a perpendiicular(X) magnetic field B.Find the force of compression in the wirre.GIVEN[magnetic field is X cross,and the current is anticlockwise]
3.suppose the radius of cross section os the wire used in the problem above is r.FInd the increase in radius of the loop if the magnetic field is switched off.youngs modulus of material is Y
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5 Answers
11
62virang.. i think rohit is looking for the proof of this general result!
I mean this result is something that I am not a very big fan of unless you know the proof well :P :)
11Ans2)
Consider a small part of ring of radius a.
The forces acting are shown.
Fm is the magnetic force of small element
For samll angle d 8 , sin d8 = d8 (approx.) (here 8 = theta)
Equating horizontal and vertical forces, we get
2 T d8 = I (2a d8) B (where T is the tension or force of compression and B is the magnetic field)
(Fm = I 2a d8 B) bcoz Fm = I L B
On solving we get,
T = I a B (Force of compression )