A magnetic compass needle is placed in the plane of paper near point A as shown in Figure 13.6.
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?
Ans. In the plane of the paper itself. The axis of the compass is vertical and
the field due to the conductor is also vertical. It could result in a dip of
compass needle which is not possible in this case (dips result only if axis of
compass is horizontal). The deflection is maximum when the conductor through A
is perpendicular to the plane of paper and the field due to
it is maximum in the plane of the paper.
