Class 12th Physics Magnetism and Matter NCERT Notes CBSE 2023

Chapter 5 Magnetism and Matter

Chapter 5 of NCERT notess for Grade 12 Physics includes detailed step-by-step solutions to all textbook problems. Magnetism and matter are two of the most important concepts covered in the NCERT notes for Grade 12 Physics, which require a lot of creativity. Magnetism is not only about magnets but also about phenomena and concepts used in various applications.

University experts design NCERT notes in Vidyakul. Furthermore, Vidyakul provides practice questions on its learning platform to help students understand the chapter. These practice questions help students explore 49 concepts explained byVidyakul. Therefore, to achieve good results, students must thoroughly solve all questions using NCERT notes.

Points to Remember

Some of the important points to remember from the chapter are as follows:

• There are two poles, one north and one south. Magnetic poles that are similar repel, while those that are dissimilar attract.

• Therefore, there are no magnetic monopoles. Cutting a magnet in half yields two smaller magnets.

• Also, a geographic meridian is a vertical plane that passes through a geographic axis.

• Magnetic meridian is a vertical plane that passes through magnetic axis.

• The Curie temperature is the temperature at which the transition from ferromagnetism to paramagnetism occurs.

• Besides, permanent magnets are substances that, at room temperature, retain their ferromagnetic property for an extended period of time.

Topics and Sub-topics

Chapter 5 of Vidyakul Grade 12 Physics notes will help students grasp the brief concept of magnetism and matter. The magnetism of matter refers to the force exerted by magnets to attract or repel each other. The magnetic moments and currents of some elementary particles produce a magnetic field. It also affects other magnetic moments and currents.

 Sections Topics Description Ex 5.1 The Bar Magnet Ex 5.2 The Magnetic Field Lines Ex 5.3 Bar Magnet as an Equivalent Solenoid Ex 5.4 The Dipole in a Uniform Magnetic Field Ex 5.5 The Electrostatic Analogue Ex 5.6 Magnetism and Gauss’s law Ex 5.7 The Earth’s Magnetism Ex 5.8 Magnetic Declination and Dip Ex 5.9 Magnetisation and magnetic intensity Ex 6.0 Magnetic properties of materials Ex 6.1 Diamagnetism Ex 6.2 Paramagnetism Ex 6.3 Ferromagnetism Ex 6.4 Permanent Magnets and electromagnets

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Few Important Questions

• As we go from the magnetic equator towards the geographical south pole, what will be the angle of the dip?

As we move from the equator to Geographical south pole (which is near the magnetic north pole), the vertical component of earth’s magnetic field increases, and hence, angle of dip goes on increasing. At the two magnetic poles, the magnetic needle rests vertically, such that the angle of descent at the two poles is 900. On the magnetic equator, the magnetic needle rests horizontally, such that the dip angle is 00.

• A magnetising field of 5000 A/m produces a magnetic flux of 5 × 10−5 wb in an iron rod is 0.5 cm2, then what is the permeability of the rod?

The permeability of the rod will be 2 × 10−4 H/m.

• The poles of a horse-shoe magnet each of pole strength 2 Am are 4 cm apart. What is the magnetic moment of the horse-shoe magnet?

The magnetic moment of the horse-shoe magnet is 0.08 Am2.

Practice Questions

1. Answer the following questions regarding earth’s magnetism:

1. With the specification of the earth’s magnetic field, name the independent quantities.

2. In southern India, If the angle of dip at a location is about 30°, do we expect a greater or smaller dip angle in Britain?

3. If we made a map of magnetic field lines at New Delhi, would the lines come out of the ground or go into the ground

4. In which direction would a compass be free to move in the vertical plane point if the compass is located right on the geomagnetic north or south pole?

5. Check the order of magnitude of the earth’s field if the dipole of the magnetic moment is 20 × 1022 J T–1 and is located at its center.