B=2rμ0I.
When n turns are made, radius becomes r′.
n×2πr′=2πr⇒r′=nr.
Now, B′=2r′μ0nI=n22rμ0I=n2B.
NEET UG 2016 — Physics Electromagnetism
A long wire carrying a steady current is bent into a circular loop of one turn. The magnetic field at the centre of the loop is B. It is then bent into a circular coil of n turns. The magnetic field at the centre of this coil of n turns will be
Held on 30 Apr 2016 · Verified 9 Jul 2026.
nB
n2B
2nB
2n2B
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