MAGNETIC EFFECT OF CURRENT, CBSE CLASS XII, PHYSICS NOTES PART I

 

CBSE CLASS XII, MAGNETIC EFFECT OF CURRENT, PHYSICS NOTES-(PART I)

MAGNETIC EFFECT OF CURRENT


NCERT Class XII Physics Chapter 4th. Magnetic Effect of Current Notes

Study Material and Notes of Chapter 3 Magnetic Effect of current Class XII Physics

ACCORDING TO THE CBSE SYLLABUS 2025-26.

When current is passed through the conductor it will produce a magnetic effect around it, so basically the wire acts like a magnet, and it will interact with the permanent magnet you have placed next to it, this effect can be reversed by changing the direction of the current, which according to the rule changes the direction of the magnetic field produced by it.

 OERSTED EXPERIMENT

a. Oersted discovered that a magnetic field around a conductor carrying electric charge at rest produces an electric field around it.
b. A current-carrying conductor has a magnetic field and not an electric field around it. On the other hand, a charge moving with a uniform velocity has both an electric and a magnetic field around it.
c. An electric field cannot be produced without a charge, whereas a magnetic field can be produced without a magnet.
d. No poles are produced in a coil carrying current, but such a coil shows north and south polarities.
e. All oscillating or accelerated charge produces E.M. waves, in addition to electric fields.

MAGNETIC INDUCTION IS A VECTOR QUANTITY

Not uncommonly, it is given by the number of lines of induction threading a unit area normal to the surface.                         Magnetic field S.I. UNIT is tesla or weber/metre2.


MAGNETIC FIELD DUE TO A MOVING POINT CHARGE


μo ≡ 4π × 10-7 N·s2/C2 is called the permeability of free space.

BIOT SAVART LAW

With the help of experiment result, Biot and Savart arrived at a mathematical expression that magnetic field at some point in terms of the current that produces the field. That expression is based on the following experimental observation for the magnetic field at a point a.



Thus, One tesla is 10 -7 times the magnetic field produced by a conducting wire of length one metre and carrying current of one ampere at a distance of one metre from it and perpendicular to it.                               

MAGNETIC FIELD DUE TO A STRAIGHT WIRE
BIOT-SAVART LAW AND COULOMB’S LAW COMPARISON


POINT OF SIMILARITY

1. Both fields depend inversely on the square of the distance from the source to the point of observation.

2. Bothare long range field.

3 The principle of superposition is applicable to both fields. This is because the magnetic field is linearly related to its source, namely, the current element and the electrostatic field is related linearly to its source, that is electric charge.

POINT OF SIMILARITY

1. The magnetic field is produced by a vector source ( the current element). The electrostatic field is produced by a scalar source (the electric charge).
2. the direction of the electrostatic field is along displacement vector joining the source and the field point. The direction of the magnetic field is perpendicular to the plane containing the current element.
3. In Biot-Savart law, the magnitude of  the magnetic field is proportional to the sine of the angle between the current element and displacement vector. But there is no such angle dependence in the coulomb’s law for the electrostatic field.

MAGNETIC FIEL DUE TO A LONG STRAIGHT CURRENT CARRYING CONDUCTOR




Consider a straight conductor XY carrying current I. We wish to find its magnetic field at the point p whose perpendicular distance from the wire is a (PQ = a).
Consider a small current element Dl of the conductor at o. Its distance from Q is l. Let r be the position vector of point p relative to the current element and θ be the angle between dl and r. according to Biot Savart law the magnitude of the field due to the current element will be









Comments

Post a Comment

please do not enter any spam link in the comment box

Popular posts from this blog

FORCE AND LAWS OF MOTION, Class IX, Part 4

Image
  If a boy wearing roller skates stands facing a wall and pushes the wall with his hands, the boy finds himself moving backward, away from the wall. It appears as if the wall also pushes the boy away. When the boy exerts a force on the wall by pushing it with his hands, then the wall exerts an equal force on the boy in the opposite direction . Since the boy is wearing roller skates, the opposite force exerted by the wall makes him backward, the boy on roller skates is exerting force on the wall towards the left side. The wall exerts an equal force on the boy towards the right side. Due to this, the boy moves in the backward direction. From this discussion, we conclude that when a boy exerts a force on the wall, the wall exerts an equal and opposite force on the boy . This is just an illustration of Newton’s third law of motion. Whenever one body exerts a force on another body, the second body exerts an equal and opposite force on the second body. The force exerted by the firs...
Read more

FORCE AND LAWS OF MOTION, Class IX, Part 3

Image
                                         In order to understand Newton’s second law of motion, we should first know the meaning of the term momentum of a moving body (or moving object). We know that a cricket ball is much heavier than a tennis ball. Suppose we throw a cricket ball and a tennis ball, both with the same speed or velocity. It will be found that more force is required to stop the cricket ball (Which has more mass) and less force is required to stop the tennis ball (which has less mass). We conclude that the force required to stop a moving body is directly proportional to its mass. If we throw two cricket balls of the same mass at different speeds or velocities, it will be found that more force is required to stop that cricket ball which is moving with higher velocity and less force is required to ...
Read more

ELECTRIC CHARGES AND FIELDS, CBSE CLASS XII, PHYSICS NOTES PART I

Image
  CBSE CLASS 12 PHYSICS NOTES   CHAPTER 1 ELECTRIC CHARGES AND FIELDS   Here are the notes for CBSE Class 12 Physics Chapter 1 Electric Charges and Fields. This chapter explains the basics of electric charges and the electric fields they create. It includes key concepts like Coulomb's Law, which describes the force between two charged objects, and the superposition principle, which helps calculate the total electric field from multiple charges. You'll also learn about electric field lines, their properties and electric flux. These concepts are essential for understanding how electric forces work. You can find the full notes through the link provided for more details. INTRODUCTION Electric charges and fields are fundamental concepts in the study of electrostatics, a branch of physics that deals with the forces exerted by charges at rest. This study note will break down these concepts into digestible sections, providing clear explanations, examples, and important ...
Read more