KEAM 2019 Physics and Chemistry Paper

Two parallel conductors 1 and 2 carrying current I1 and I2, respectively of length l is shown in the figure given belowForce on wire 2 due to B1 is given by
F2=I2lB1
Using right hand screw rule, direction of F2 would be towards wire 1 .
Similarly, force on wire due to B2 (field of wire 2)
F1=I1lB2
Again, by using right hand screw rule, direction of F1 would be towards 2.
If two parallel conductors carry (equal or unequal) current in same direction, they will exert force towards each other i.e., they will attract.
However, if these parallel conductors have current in the opposite direction then they will exert force away from each other such that they would repel.