Question

A solenoid with a soft iron core is called _______.
A. electromagnet
B. magnet
C. conducts
D. insulator

Answer 1

Hint: Solenoid is a coil of wire. When current passes through it a magnetic field is created. If we put a conducting material inside the solenoid, it can be used as a magnet. This magnet shows all the properties of a general magnet.

Complete answer:
A solenoid is a long coil with a large number of turns of copper wire. When current is passed through the solenoid, a magnetic field is produced in the solenoid which is the same as the magnetic field due to a bar magnet. One end of the solenoid acts as the north pole and the other end of the solenoid will act as the south pole.

When a soft iron core is placed inside the solenoid, the strength of the magnetic field due to the solenoid becomes very large. This is because the soft iron core is magnetized by induction. This combination of the solenoid and the soft iron core is called an electromagnet.

So, the correct answer is “Option A”.

Additional Information:
Electric current is used to make temporary magnets known as electromagnet. An electromagnet acts as a magnet only if the current is flowing through the solenoid. If the current through the solenoid is stopped, the soft iron core losses all its magnetism and the electromagnet stop working.

Note:
To make permanent magnets, we use steel, because even if we stop the current through the solenoid the steel does not lose all its magnetism. The electromagnets are used in motors or generators, transformers etc.