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Moving Charges and Magnetism — Physics STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 SciencePhysicsMoving Charges and Magnetism3 Marks
Question
A rectangular wire loop of width a is suspended from the insulated pan of a spring balance, as shown in A current i exists in the anti-clockwise direction in the loop. A magnetic field Bexists in the lower region. Find the change in the tension of the spring if the current in the loop is reversed.

✓

Answer


Current anticlockwise

Since the horizontal Forces have no effect.

Let us check the forces for current along AD & BC [Since there is no $\overrightarrow{\text{B}}$ ]

In AD, F = 0

For BC

F = iaB upward

Current clockwise

Similarly, F = - iaB downwards

Hence change in force = change in tension

= iaB - (-iaB) = 2 iaB

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