Question

A straight current carrying conductor is kept along the axis of circular loop carrying current. The force exerted by the straight conductor on the loop is

• A. perpendicular to the plane of the loop
• B. in the plane of the loop, away from the center
• C. in the plane of the loop, towards the center
• D. zero

Answer 1

Answer: (D)

Magnetic field lines of circular loop carrying current on the axis of the loop is along the axis of the loop itself. When a straight current carrying conductor is placed along the axis of the loop, the magnetic field lines are along the loop and have no component perpendicular to the direction of current. Hence, net force on the current carrying conductors is zero.