A current-carrying circular loop of radius R is placed in the x-y plane with center at the origin. Half of the loop with x > 0 is now bent so that it now lies in the y-z plane.
 
1. The magnitude of the magnetic moment now diminishes.
2. The magnetic moment does not change.
3. The magnitude of B at (0, 0, z), z >>R increases.
4. The magnitude of B at (0, 0, z), z >>R is unchanged.

(a) Hint: Apply Fleming's left-hand rule to find the direction of the resultant magnetic field.
Step 1: Initially, the magnetic moment is given by;
M=I×πR2
Step 2: When the loop is bent, the magnetic moment of each half-loop;
M1=M2=I×πR22
So, the net magnetic moment is given by;
M'=M12+M22=I×πR22×2=I×πR22<M