A long wire carrie scurrent of `25` A parallel to the positive x axis, except for three of the four segments that follow the edges of a cube of side `0.4 m`, as shown in figure. The wire is in a uniform magnetic field of `2.0T` directed paralled to the positice x axis. What is the net magnetic force on the wire (in newton) ?

Options

A. `20 hat(j)`
B. `20 hat(k)`
C. `20 (hat(j) - hat(k))`
D. `-20 hat(j)`

Answer

D

Explanation

Force `= 25(0.4 hat(i) - 0.4 hat(k)) xx 2 hat(i) = -20 hat(j)`