question_answer

One metre length of wire carries a constant current. The wire is bent to form a circular loop. The magnetic field at the centre of this loop is B. The same is now bent to form a circular loop of smaller radius to have four turns in the loop. The magnetic field at the centre of this new loop is

A)            4 B 

B)            16 B

C)            \[B/2\]                                    

D)            \[B/4\]