Question

A magnetic compass needle is placed in the plane of paper near point A as shown in Figure 13.6. In which plane should a straight current carrying conductor be placed so that it passes through A and there is no change in the deflection of the compass? Under what condition is the deflection maximum and why?

Answer 1

According to the Right hand thumb rule, the direction of the magnetic field is perpendicular to the direct of the current and if a magnetic compass is brought closer to the current carrying conductor, the deflection is maximum. But when the needle is placed near the point A on the plane as that of the paper as given in the figure, there is no deflection. Hence, the current carrying conductor needs to be placed in the same plane as that of the paper, for the magnetic compass to attain no deflection.