Magnetic Field of Straight Wires
A circular coil of radius is carrying a current in anti-clockwise sense. A long straight wire is carrying current in the negative direction of -axis. Both are placed in the same plane and the distance between centre of coil and straight wire is . The magnetic field at the centre of coil will be zero for the value of equal to
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Answer: (a)
- Coil at centre: ; wire at distance : .
- The directions are opposite, so when .
- So the answer is (a).