A conducting loop carrying a current `I` is placed in a uniform magnetic field pointing into the plane of the paper as shown. The loop will have a tendency to

Options

A. contract
B. expand
C. move towards positive X- axis
D. move towards negative X - axis.

Answer

b

Explanation

Length vector is along the tangent and magnetic field is into the plane of paper. Hence direction of cross product `I vec (dl) xx vec B` is radially outward at all the points of the loop, according to the Fleming.s left-hand rule. This magnetic force will develop the tensile stress. Hence, tensile stress will be developed in the loop and hence there will be a tendency to expand. Hence, option (b) is correct.