A thin sheet of high-permeability iron is inserted between a small bar magnet and a…
PHYSICS · Single correct · CBSE · Physics · Magnetism and Matter · Magnetism and Matter
Problem
A thin sheet of high-permeability iron is inserted between a small bar magnet and a sensor that measures the magnetic field at a fixed point 0.30m from the magnet along the axial line. The sheet fills the entire cross-section between the magnet and the sensor. Which statement best describes how the magnitude of the field measured at the sensor changes after the sheet is inserted?
(a) B becomes nearly zero; the iron sheet blocks virtually all magnetic field lines from reaching the sensor.
(b) B decreases but remains non-zero because much of the flux is diverted into the high-permeability sheet rather than through the air path to the sensor.
(c) B remains essentially unchanged; the sheet has no effect on the external magnetic field.
(d) B increases; the sheet reflects and focuses field lines toward the sensor, concentrating the flux.