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Question
A circular coil having N turns of radius R carrying a current I is used to produce a magnetic field B at its centre O.
If this coil is opened and rewound such that the radius of the newly formed coil is 2R, carrying the same current I, what will be the magnetic field at the centre O?
Options
2B
B
`"B"/2`
`"B"/4`
Solution
`"B"/4`
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