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Question
Draw the magnetic field lines due to a circular loop area `vecA` carrying current I. Show that it acts as a bar magnet of magnetic moment `vecm = IvecA .`
Solution
When a circular loop of area A carries a current I, the loop creates a magnetic field around it. The strength of the magnetic field created depends on the current through the conductor. At the centre of the loop, the magnetic field lines are perpendicular to the plane of the loop which provides the magnetic moment, m = IA. Hence, it behaves like a magnet. The comparison between the magnetic field lines around a current-carrying loop and a bar magnet shows that the two patterns are similar.
If the current in the loop is in the anticlockwise direction, a North Pole is formed and if the current is in the clockwise direction, a South Pole is formed.
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