Answer to Question #41094 in Electricity and Magnetism for Sanjeev

Question

A straight section PQ of a circuit lies along the X-axis from x = a/2 to –a/2 and carries a steady current I. The magnetic field due to the section PQ at a point X = + a will be :-
(1) Proportional to a
(2) Proportional to a^2
(3) Proportional to 1/a
(4) Zero