Question

A current I flows in a conducting wire of lenth L. If we bent it in a circular form, then calculate its magnetic dipole moment.
A. `(ll)/(4pi)`
B. `(l^(2)l)/(4pi)`
C. `(ll^(2))/(4pi)`
D. `(l^(2)l^(2))/(4pi)`

Answer 1

Correct Answer - B
Length of a conducting wire, `2pir=l, r=(l)/(2pi)`,
Area of coil, `alpha=pir^(2)=(pi.l^(2))/(4pi^(2))=(l^(2))/(4pi)`
`So, " " m=lA=(ll^(2))/(4pi)`