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# NCERT Solutions for Class 12 Physics Chapter 4 - Moving Charges and Magnetism - PDF Download

The 4th chapter of NCERT Physics class 12 is all about magnetism and moving charges. While preparing this topic, you will come across different other related concepts like a magnetic field, magnetic force, the motion of a charged particle in a magnetic field and so on. However, studying all these concepts and topics without proper help may look challenging. To overcome this challenge, you can take the help of NCERT solutions for class 12 Physics chapter 4 which is available on eSaral webpage for free in pdf format.

Chapter 4 Moving charges and Magnetism has a total 11 subtopics. You must focus on gaining in-depth knowledge in all these areas to secure good marks in your exams. To help you in this process, you can take the help of NCERT solutions for class 12 Physics chapter 4 provided by our expert teachers. These solutions are specially designed to make this topic understandable.

There are a total of 28 questions in the exercise of this chapter. Most of the questions are based on calculations. To solve these questions, you must have a clear concept of all the topics given in the chapter.

If you are facing difficulty in solving these sums or the other questions can consider referring to NCERT solutions for class 12 Physics Chapter 4 Moving Charges and Magnetism. As most of the questions are numerical based, everyone should cross-check it from the solutions book. These solutions will help you to identify your mistakes and correct them.

### Subtopics of NCERT Class 12 Physics Chapter 4 Moving Charges and Magnetism

 Section Number Topic 4.1 Introduction 4.2 Magnetic Force 4.2.1 Sources and Fields 4.2.2 Magnetic Field, Lorentz Force 4.2.3 Magnetic Force on a current-carrying Conductor 4.3 Motion in a Magnetic Field 4.4 Magnetic Field Due to a Current Element, Biot-Savart Law 4.5 Magnetic Field on the Axis of a Circular Current Loop 4.6 Ampere’s Circuital Law 4.7 The Solenoid 4.8 Force between Two Parallel Currents, The Ampere 4.9 Torque on Current Loop, Magnetic Dipole 4.9.1 Torque on a Rectangular Current Loop in a Uniform Magnetic Field 4.9.2 Circular Current Loop as a Magnetic Dipole 4.10 The Moving Coil Galvanometer

### Magnetic Force

Magnetic force is a result of electromagnetic force and is caused due to the motion of charges. We have already learned that a moving charge surrounds itself with a magnetic field. With this context, the magnetic force can be described as a force that arises due to interacting magnetic fields. Learn more about magnetic force in detail.

### Magnetic Field, Lorentz Force

Lorentz force is defined as the force exerted on a charged particle q moving with velocity v through an electric field E and magnetic field B. The entire electromagnetic force F on the charged particle is called the Lorentz force and is given by

F = qE + qv × B.

### Magnetic Force on a Current-Carrying Conductor

The magnetic force on current-carrying conductors is given by. F=IlBsinθ, F = I l B sin θ , where I is the current, l is the length of a straight conductor in a uniform magnetic field B , and θ is the angle between I and B .

### Motion in a Magnetic Field

Charged particle movement in an electric and magnetic field q = F (v x B). As the mechanical field is directed towards the particle's circular motion, it forms a centripetal force.

### Magnetic Field Due to a Current Element, Biot-Savart Law

Biot-Savart Law says that if a current carrying conductor of length dl produces a magnetic field dB, the force on another similar current carrying conductor depends upon the size, orientation and length of the first current carrying element.

### Magnetic Field on the Axis of a Circular Current Loop

The magnetic field due to the circular current loop of radius a at a point which is a distance R away, and is on its axis, So B =2(R+x)μIx.

### Ampere’s Circuital Law

Ampere's circuital law says that the line integral of the magnetic field surrounding closed-loop equals to the number of times the algebraic sum of currents passing through the loop, this law holds for steady currents which do not fluctuate with time.

### The Solenoid

A solenoid is a type of electromagnet which is formed by a helical coil of wire whose length is considerably greater than its diameter, which generates a controlled magnetic field. The coil can produce a uniform magnetic field in a volume of space when an electric current is passed through it.

### Force Between Two Parallel Currents, The Ampere

When the parallel wire turns in opposite directions, the wires push each other. The wires pull on each other when the current in the wire flows in the same direction. And they flow after each other when the currents are opposite.

### Torque on a Rectangular Current Loop in a Uniform Magnetic Field

When the magnetic field B is in the plane with the rectangular loop and no force is exerted by the field on the arms of the loop that is parallel to the magnets, but the arms perpendicular to the magnets experience a force.

### Circular Current Loop as a Magnetic Dipole

The magnetic field at large distance due to current in a circular current loop is very similar in behaviour to the electric field of an electric dipole.

### The Moving Coil Galvanometer

Moving coil galvanometers work on the principle that a current-carrying coil experiences torque when placed in a magnetic field. As the electric current is passed through the coil, a torque acts on it, which distracts the coil.

## Benefits of Class 12 Chapter 4 Physics NCERT Solutions

The key features of NCERT Solutions for Class 12 Physics Chapter 4 are as mentioned down below

1. Highly experienced expert teachers design the solutions.

2. The solutions are based on the NCERT textbook prescribed by your board exams.

3. The PDF of solutions are available on our page with a free download option.

4. Each and every problem is solved precisely as per the marks weightage allotted in your board exams.

#### FAQs

Question 1 : What are the topics in chapter 4 Moving Charges and Magnetism?

Answer: Following are the subtopics of chapter 4 Moving Charges and Magnetism

4.1 Introduction

4.2 Magnetic Force

4.2.1 Sources and Fields

4.2.2 Magnetic Field, Lorentz Force

4.2.3 Magnetic Force on a current-carrying Conductor

4.3 Motion in a Magnetic Field

4.4 Magnetic Field Due to a Current Element, Biot-Savart Law

4.5 Magnetic Field on the Axis of a Circular Current Loop

4.6 Ampere’s Circuital Law

4.7 The Solenoid

4.8 Force between Two Parallel Currents, The Ampere

4.9 Torque on Current Loop, Magnetic Dipole

4.9.1 Torque on a Rectangular Current Loop in a Uniform Magnetic Field

4.9.2 Circular Current Loop as a Magnetic Dipole

4.10 The Moving Coil Galvanometer