Question 7 - Past Year - 5 Mark Questions - Chapter 13 Class 10 - Magnetic Effects of Electric Current

What is an electromagnet? List any two uses.

(i) Draw a labelled diagram to show an electromagnet is made.

(ii) State the purpose of soft iron core used in making an electromagnet.

(iii) List two ways of increasing the strength of an electromagnet if the material of the electromagnet is fixed.

Answer:

An electromagnet is a magnet consisting of wire wound around a soft iron core . It is magnetized only when electric current is passed through the coil.

Uses of electromagnet:

• They are used in headphones and loudspeakers.
• They are used in magnetic locks.

(i)

Diagram to show how an electromagnet is made: 

(ii)

A soft iron core is used in making an electromagnet because it has the property of losing all its magnetism when the current is switched off and gaining it all back when the current is switched on and it also increases the magnetism of a solenoid by a thousand fold.

(iii)

Ways to increase the strength of an electromagnet if the material of the electromagnet is fixed are: 

• Increasing the number of turns in the coil.
• Increasing the amount of current flowing through the coil.