PHYSICS · Multi-part · CBSE · Physics · Magnetic Effects of Electric Current · Magnetic Effects of Electric Current
Problem
In the laboratory, a student sketches two magnetic field lines emerging from the North pole of a bar magnet. At point A on one line, the perpendicular distance to the nearest adjacent line is 1.5mm. At point B on the other line, the corresponding distance is 4.5mm. Treat the magnetic field strength at any point as inversely proportional to this perpendicular spacing.
(i) Calculate the ratio of magnetic field strengths BBBA at the two points.
(ii) If the magnetic field strength at A is 0.60T, estimate the magnetic field strength at B.
(iii) Briefly explain why such large field strengths are seldom realised in everyday bar magnets despite the closeness of field lines in textbook diagrams.