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A circular coil of radius 'r' having 'n'...

A circular coil of radius `'r'` having `'n'` turns carries a current `'I'`. The magnetic induction at the center of the coil is `'B'`. Now the coil is unwound and rewound with half the original radius. If the magnetic induction at the center of the coil is to be the same, the current that should be passed through the coil is

A

`2i`

B

`i`

C

`i//2`

D

`i//4`

Text Solution

Verified by Experts

The correct Answer is:
4
`n_(1)r_(1)=n_(2)r_(2),B=(mu_(0)ni)/(2r)`
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