Question

A solenoid is used as a temporary magnet (an electromagnet). Why is a soft iron core preferred as compared to steel core?

• A. Soft Iron retains its magnetism when current is switched off whereas Hardened steel loses its magnetism
• B. Soft Iron quickly loses its magnetism when current is switched off whereas Hardened steel retains its magnetism
• C. Soft Iron creates a fluctuating magnetic field when current flows through it whereas Hardened steel retains its magnetism
• D. Soft Iron quickly loses its magnetism when current is switched off whereas Hardened steel has a weak temporary magnetic field
• E. Soft Iron has a fixed magnetism when whereas Hardened steel has fluctuating magnetism

Answer 1

The correct option is B

Soft Iron quickly loses its magnetism when current is switched off whereas Hardened steel retains its magnetism

The most interesting feature of the electromagnet is that when the electrical current is turned off, the magnetism is also turned off. The core of solenoid is made of soft iron, as it quickly loses its magnetism when current is switched off. Hardened steel retains its magnetism, thus rendering a solenoid a permanent magnet.