# Notes And Questions NCERT Class 12 Physics Chapter 5 Magnetism And Matter

Please refer to Magnetism And Matter Class 12 Physics Notes and important questions below. The Class 12 Physics Chapter wise notes have been prepared based on the latest syllabus issued for the current academic year by CBSE. Students should revise these notes and go through important Class 12 Physics examination questions given below to obtain better marks in exams

## Magnetism And Matter Class 12 Physics Notes and Questions

The below Class 12 Magnetism And Matter notes have been designed by expert Physics teachers. These will help you a lot to understand all the important topics given in your NCERT Class 12 Physics textbook. Refer to Chapter 5 Magnetism And Matter Notes below which have been designed as per the latest syllabus issued by CBSE and will be very useful for upcoming examinations to help clear your concepts and get better marks in examinations.

• Magnetic materials tend to point in the north – south direction.
• Like magnetic poles repel and unlike ones attract.
• Magnetic poles cannot be isolated.

• Gauss’s Law for Magnetism:
It states that the net magnet flux through any closed surface is zero

• Poles:
a) The pole near the geographic north pole of the earth is called the north magnetic pole.
b) The pole near the geographic south – pole is called the south magnetic pole.
c) The magnitude of the magnetic field on the earth’s surface = 4 x 1o-s T.

• Elements of the Earth’s Magnetic Field:
Three quantities are needed to specify the magnetic field of the earth on its surface,
a) The horizontal component
b) The magnetic declination c) The magnetic dip.
These are known as the elements of the earth’s magnetic field.

• Magnetic Intensity:

Where x is the magnetic susceptibility of the material and μ, is the relative magnetic permeability.

• Relationship between μ, μ0 and μr:
The magnetic permeability area, μ is related as,
μ= μ0μ,
μr=l+x

• Classification of Magnetic Materials: Magnetic:
materials are broadly classified as, a) Diamagnetic
b) Paramagnetic
c) Ferromagnetic

• Magnetic Susceptibility of the Material for Magnetic Materials:
a) For diamagnetic materials zis negative and small.
b) For paramagnetic materials zis positive and small.

• Permanent Magnets:
Substances which retain their ferromagnetic property for a long period of time at room temperature are called permanent magnets.