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Question
A straight wire is held vertical and current is passed in it in the upward direction. A compass needle is kept near the wire in north of it. How is the needle deflected? What is the change in the deflection of the needle if the current in wire is reversed?
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Solution
When the current in the wire is upwards, the needle will deflect with its north pole towards west.
If the current in the wire is reversed, the north pole of the needle will deflect towards east.
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