Advertisements
Advertisements
Question
State two differences between an electromagnet and a permanent magnet.
Advertisements
Solution
| Electromagnet | Permanent magnet | |
| i. | It is made up of soft iron. | It is made up of steel. |
| ii. | The magnetic field strength can be changed. | The magnetic field strength cannot be changed. |
| iii. | Electromagnets of very strong field can be made. | Permanent magnets are not so strong. |
APPEARS IN
RELATED QUESTIONS
Why is soft iron used as the core of the electromagnet in an electric bell?
The incomplete diagram of an electric bell is given in Figure. Draw winding of coil on the core and complete the electric circuit in the diagram.
G-Gong, H-Hammer, A-Armature, C-Core, B-Battery.
Name one device that uses an electromagnet.
Name the material used for preparing an electromagnet.
How is an electromagnet made? Name two factors on which the strength of magnetic field of the electromagnet depends.
You are required to make an electromagnet from a soft iron bar by using a cell, an insulated coil of copper wire and a switch.
- Draw a circuit diagram to represent the process.
- Label the poles of the electromagnet.
A coil of insulated copper wire is wound around a piece of soft iron and current is passed in the coil from a battery. What name is given to the device so obtained? Give one use of the device mentioned by you.
Show with the aid of a diagram how a wire is wound on a U-shaped piece of soft iron in order to make it an electromagnet. Complete the circuit diagram and label the poles of the electromagnet.
State two ways through which the strength of an electromagnet can be increased.
State two advantages of an electromagnet over a permanent magnet.
Why is soft iron used as the core of the electromagnet in an electric bell?
How is the working of an electric bell affected, if alternating current be used instead of direct current?
Name the material used for making the armature of an electric bell. Give a reason for your answer.
Explain, why steel is used in preference to soft iron for making permanent magnets while soft iron is used in preference to steel for making electromagnets.
Explain in detail the application of electromagnets.
Explain the working of the following device.
Speaker
