The magnetic moment of a circular coil carrying current is
A
Directly proportional to the length of the wire in the coil
B
Inversely proportional to the length of the wire in the coil
C
Directly proportional to the square of the length of the wire in the coil
D
Inversely proportional to the square of the length of the wire in the coil
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C
Directly proportional to the square of the length of the wire in the coil
c (c) $M = NiA \Rightarrow M \propto A$$ \Rightarrow M \propto {r^2}$$\left( {{\rm{As}}\;l = 2\pi r \Rightarrow l \propto r} \right)$
$==>$ $M \propto {l^2}$
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