(a) What is an electromagnet ? Describe the construction and working of a electromagnet with the help of a labelled diagram.
(b) Explain why an electromagnet is called a temporary magnet.
(c) Explain why the core of an electromagnet should be made of soft iron and not of steel.
(d) State the factors on which the strength of an electromagnet depends. How does it depend on these factors ?
(e) Write some of the important uses of electromagnets.
(a) What is an electromagnet ? Describe the construction and working of a electromagnet with the help of a labelled diagram.
(b) Explain why an electromagnet is called a temporary magnet.
(c) Explain why the core of an electromagnet should be made of soft iron and not of steel.
(d) State the factors on which the strength of an electromagnet depends. How does it depend on these factors ?
(e) Write some of the important uses of electromagnets.
(a) An electromagnet is a temporary magnet that works on the magnetic effect of current. It consists of a long coil of insulated copper wire wrapped around a soft iron core that is magnetised ony when electric current is passed through the coil.
To make an electromagnet, we take a rod NS of soft iron and wind a coil C of insulated copper wire around it. When the two ends of the copper coil are connected to a battery, an electromagnet is formed.
(b) An electromagnet is called a temporary magnet because it produces magnetic field so long as current flows in its coil.
(c) Core of an electromagnet should be of soft iron and not of steel because soft iron loses all its magnetism when current in the coil is switched off but steel does not lose its magnetism when the current is withdrawn.
(d) Strength of electromagnet depends on:
i. The number of turns in the coil – Increasing the number of turns in the coil increases the strength of the electromagnet.
ii. The current flowing in the coil – Increasing the current flowing in the coil increases the strength of the electromagnet.
iii. The length of air gap between its poles: Reducing the length of air gap between the poles of electromagnet increases the strength of the electromagnet.
(e) Electromagnets are used in several electrical devices such as electric bell, electric motor, loudspeaker etc. They are also used by doctors to remove particles of iron or steel from a patient’s eye and to remove pieces of iron from wounds.
(a) An electromagnet is a temporary magnet that works on the magnetic effect of current. It consists of a long coil of insulated copper wire wrapped around a soft iron core that is magnetised ony when electric current is passed through the coil.
To make an electromagnet, we take a rod NS of soft iron and wind a coil C of insulated copper wire around it. When the two ends of the copper coil are connected to a battery, an electromagnet is formed.
(b) An electromagnet is called a temporary magnet because it produces magnetic field so long as current flows in its coil.
(c) Core of an electromagnet should be of soft iron and not of steel because soft iron loses all its magnetism when current in the coil is switched off but steel does not lose its magnetism when the current is withdrawn.
(d) Strength of electromagnet depends on:
i. The number of turns in the coil – Increasing the number of turns in the coil increases the strength of the electromagnet.
ii. The current flowing in the coil – Increasing the current flowing in the coil increases the strength of the electromagnet.
iii. The length of air gap between its poles: Reducing the length of air gap between the poles of electromagnet increases the strength of the electromagnet.
(e) Electromagnets are used in several electrical devices such as electric bell, electric motor, loudspeaker etc. They are also used by doctors to remove particles of iron or steel from a patient’s eye and to remove pieces of iron from wounds.
