Unit - 7 Magnet

 Unit - 7

Magnet

summary

1. The magnetic force in a magnet is called magnetism.

2. A magnet is a very useful object.

3. A magnet attracts magnetic objects.

4. The strength of the magnet is concentrated towards the side.

5. A magnet kept free to rotate is always “north and south” of the earth

Sits down.

6. Like poles of two magnets repel each other and opposite poles attract

it happens

7. The north and south poles of a magnet never separate.

8. Objects that are affected by magnets are called magnetic objects. Iron, nickel and cobalt

are magnetic objects.

9. The point on the side of the magnet where the magnetic force is concentrated

It is called Dhruva.

10. The area around the magnet up to which the magnet affects it is called the electromagnetic field.

3. Write answers to the following questions:

  (a) What is magnetism?

  (b) Name any four devices in which magnets are used.

  (c) When a magnet is suspended in iron dust, more iron dust is drawn towards its side. It is suspended, why?

  (d) Why does a bar magnet placed on a table not face north and south?

  (e) Write the names of two magnetic and two non-magnetic objects.

  (f) What is magnetic field? Which magnet has a larger field?

  (g) What is the difference between the length of a magnet and the length of a magnet? explain

Answer 👉 

(a) Magnetism is the force that attracts or repels objects made of iron, nickel, or cobalt.

(b) Four devices in which magnets are used are:

• * Speakers
• * Motors
• * Refrigerator magnets
• * Compasses

(c) When a magnet is suspended in iron dust, more iron dust is drawn towards its side because the magnet's field lines are strongest at the poles. The iron dust is attracted to the poles of the magnet.

(d) A bar magnet placed on a table does not face north and south because the Earth's magnetic field is not perfectly aligned with the north-south axis. The Earth's magnetic field is actually tilted by about 11 degrees.

(e) Two magnetic objects are a bar magnet and a compass. Two non-magnetic objects are a piece of wood and a piece of paper.

(f) A magnetic field is the region around a magnet where the force of magnetism can be detected. The strength of the magnetic field is greatest at the poles of the magnet.

(g) The length of a magnet is the distance from one end of the magnet to the other. The length of a magnet's field is the distance from the magnet where the force of magnetism can still be detected. The length of a magnet's field is always greater than the length of the magnet itself.