A circular loop and a square loop are formed from the same wire and the same current is passed through them . Find the ratio of their dipole moments.

Options

A. `4pi`
B. `4/(pi)`
C. `2/(pi)`
D. `2pi`

Answer

B

Explanation

`2pirlimpliesr=l/(2pi):.M_(1)=iA=ixxpi(l^(2))/(4pi^(2))=(il^(2))/(4pi)`
When wire formed in square loop then side of loop is `a=l/4`
`M_(2)=iA=ia^(2)=i(l^(2))/16, (M_(1))/(M_(2))=4/(pi)`