Question

Two wires each carrying a steady current I are shown in four configuration in Column I. Some of the resulting effects are described in Column II. Match the statement in Column I with the statements in Column II and indicate your answer by darkening appropriate bubbles in the 4 x 4 matrix given in the ORS. 

Column I	Image	Column II
(A) Point P is situated midway between the wires		(P) The magnetic fields (B) at P due to the currents in the wires are in the same direction.
(B) Point P is situated at the midpoint of the line joining the centers of the circular wires, which have same radii.		(Q) The magnetic fields (B) at P due to the current in the wires are in opposite directions.
(C) Point P is situated at the midpoint of the line joining the centers of the circular wires, which have same radii.		(R) There is no magnetic field at P.

Answer 1

t = MB sin 90º = 9.4 ×10^–3 Nm

(A) Magnetic field is in opposite direction. Since current is in same direction so they will attract each other. Magnetic field is equal in magnitude at P so magnetic field at P is zero.