A student sketches magnetic field lines around a bar magnet
PHYSICS · Single correct · CBSE · Physics · Magnetic Effects of Electric Current · Magnetic Effects of Electric Current
Problem
A student sketches magnetic field lines around a bar magnet. In the sketch, the lines leave the south pole and enter the north pole, with proper spacing and no intersections. Which statement correctly identifies the error in the student’s sketch?
(a) Magnetic field lines around a bar magnet should be equally spaced everywhere, so varying spacing is the real error.
(b) Field lines should leave the north pole and enter the south pole outside the magnet.
(c) Magnetic field lines cannot start or end on a magnet; they must form closed loops, so the sketch should show continuous loops instead of starting and ending at the poles.
(d) Field lines between the two poles of a bar magnet ought to be straight rather than curved; the curved lines in the sketch are therefore incorrect.