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If we double the radius of the coil keep...

If we double the radius of the coil keeping the current through it unchanged, the magnetic field on its axis at very very far away points

A

double

B

three times

C

four times

D

one - fourth

Text Solution

Verified by Experts

The correct Answer is:
C
`B_("axis")=((mu_0NI)/(2x^3))R^2`
`B propR^2`
So, when radius is doubled, magnetic field becomes four times.
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DISHA PUBLICATION-MOVING CHARGES AND MAGNETISM -EXERCISE - 1 : Concept Builder (Topic wise) (Topic 2 : Magnetic Field Lines, Biot - Savart.s Law and Ampere.s Circuital Law
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  12. The magnetic field at a distance r from a long wire carryimg current I...

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