Two wires of same length are made to from a circle and a square. They carry same current. The ratio of the magnetic moment of circle to that of square is

Step-by-step solution

Let length of wire be l . For a square loop, side of square l 4 . Hence its magnetic moment M_ sq =i A=i [ l 4 ]^2= i l^2 16 Radius of a circular loop r= l 2 Hence, its magnetic moment aligned & M_ cir =i A=i r^2 & M_ cir =i [ l^2 4 r^2 ]= i l^2 4 & M_ cir M_ sq = 4 aligned