Steel is preferred for making permanent magnets whereas soft iron is preferred for making electromagnets. Give one reason.
Solution
A permanent magnet must retain its magnetism and resist being demagnetised, so it needs high retentivity and high coercivity — properties that steel possesses.
An electromagnet must magnetise strongly when current flows and lose its magnetism as soon as the current stops, so it needs high permeability with low retentivity and low coercivity — properties of soft iron.
Hence steel suits permanent magnets and soft iron suits electromagnets.
An electromagnet must magnetise strongly when current flows and lose its magnetism as soon as the current stops, so it needs high permeability with low retentivity and low coercivity — properties of soft iron.
Hence steel suits permanent magnets and soft iron suits electromagnets.
CBSE Class 12 Board · 2006 · All India · Subjective