Advertisements
Advertisements
प्रश्न
State two differences between an electromagnet and a permanent magnet.
Advertisements
उत्तर
| 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
संबंधित प्रश्न
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.
Electromagnets are made up of :
The strength of the electromagnet can be increased by
Name the material used for preparing an 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?
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.
Unlike magnetic poles ______ whereas like poles ______.
Assertion (A): When 2 long parallel wires, hanging freely are connected in parallel to a battery, they come closer to each other.
Reason (R): Wires carrying current in opposite directions repel each other.
Explain the working of the following device.
Speaker
Explain the working of the following device.
Magnetic levitation trains.
