Question

Draw the pattern of the magnetic field lines for the two parallel straight conductors carrying current of same magnitude 'I' in opposite directions as shown. Show the direction of magnetic field at a point O which is equidistant from the two conductors. (Consider that the conductors are inserted normal to the plane of a rectangular cardboard.)

 

Hint:

In the case of parallel conductors carrying currents in opposite directions, the magnetic fields at points equidistant from both conductors will cancel each other.

Answer 1

When two conductors carry currents in opposite directions, the magnetic field produced by each conductor at any point in space will be in opposite directions. For conductors with current flowing in opposite directions, the field lines will be arranged such that: 
- For the first conductor (current flowing in one direction), the magnetic field lines will circle the conductor in a clockwise direction (if viewed from above). 
- For the second conductor (current flowing in the opposite direction), the magnetic field lines will circle the conductor in a counterclockwise direction. At a point \( O \), which is equidistant from both conductors, the magnetic field contributions from both conductors will cancel out if the currents are of equal magnitude and flow in opposite directions. The field lines will form circular loops around each conductor, with opposite directions of field due to opposite current directions.