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Illustration: Q1. A change q moves in a circular path of radius r with a speed of v. Calculate the induction of the magnetic field produced at the centre of the circle.
Solution: The equivalent current in the circular path is
I = 
B =  Q2. The coil of a galvanometer has 500 turns and each turns has an avg. area 3 x 10-4 m2. calculate the magnetic moment of the coil when a current of 0.5 A passes throgh it. If a torque of 1.5 Nm is required for this coil carrying same current to set it parallel to a magnetic field. Calculate the magnetic field.
Solution: µ = NIA
= 500 x 0.5 x 3 x 10-4
= 0.075 Am2
Also or | | = µB sin
where = angle between B and A
Here = 900
= µB sin900
B = = 20 T ASSIGNMENTS: Easy: E1. Find the magnetude of magnetic field at point P due to the current carrying wire as shown.
Solution:

1 = - 30 0 ,
2 = 60 0
 E2. Shown infigure is a conductor carrying current I. Find the magnetic field intensity at the point O.
Solution: B =
 [Due to an are]



 E3. What is the work done in transferring the wire from position (1) to position(2) ?
Solution:
The 'd' magnetic moment of the loop = I 2 l dr
B r =

U r =


-
 U = work done - (U 2 - U 1 )

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