Class 12 Physics - HARYANA
Magnetism and Matter
The chapter Magnetism and Matter in Class 12 Physics explores the magnetic properties of materials, Earth's magnetism, and bar magnets. Students learn how materials are classified into diamagnetic, paramagnetic, and ferromagnetic substances based on their response to external magnetic fields. For Haryana (BSEH) board exams, this chapter is crucial as it tests both conceptual understanding and numerical problems related to magnetic dipole moments, torque on a bar magnet, and Earth's magnetic field components. Mastering this chapter helps you score well in conceptual reasoning questions and short-answer numericals asked frequently in board papers.
Start Learning FreeKey Concepts
Bar Magnet as an Equivalent Solenoid
A bar magnet behaves similarly to a current-carrying solenoid, producing a comparable magnetic field and having analogous magnetic dipole moments.
Earth's Magnetism
Earth acts like a giant magnet due to molten core currents, defined by three elements: magnetic declination, magnetic inclination (dip), and horizontal component of Earth's magnetic field.
Magnetic Intensity and Magnetization
Magnetic intensity (H) is the magnetizing force applied, while magnetization (I) is the magnetic moment induced per unit volume in a material.
Magnetic Properties of Materials
Materials are classified into diamagnetic (repelled by magnets), paramagnetic (weakly attracted), and ferromagnetic (strongly attracted with domain structures).
Curie's Law
The magnetic susceptibility of a paramagnetic substance is inversely proportional to its absolute temperature.
Important Formulas
Board Exam Info
In the Haryana (BSEH) Class 12 Physics board exam, the chapter Magnetism and Matter usually carries around 3 to 4 marks. Questions typically include 1-mark objective questions, short-answer conceptual questions about magnetic properties or Earth's magnetic elements, and occasional small numerical problems based on susceptibility, permeability, or torque.
Frequently Asked Questions
What are the three elements of Earth's magnetic field?
The three elements are magnetic declination, magnetic inclination (or angle of dip), and the horizontal component of Earth's magnetic field.
Why do diamagnetic substances repel magnets?
Diamagnetic substances have paired electrons whose orbital magnetic moments cancel out, and when placed in a field, they induce a weak magnetic moment in the opposite direction.
What is Curie's temperature?
It is the specific temperature above which a ferromagnetic substance loses its ferromagnetism and behaves as a paramagnetic substance.
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