NCERT Solutions for Class 12 Physics Chapter 4 - Moving Charges and Magnetism - PDF Download
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eSaral > NCERT Solutions >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.
Frequently Asked Questions
Find answers to common questions.
How many questions are there in NCERT Class 12 Physics Chapter 4 exercise?
There are 28 questions in the exercise of NCERT Class 12 Physics Chapter 4 – Moving Charges and Magnetism. The majority of these questions are numerical, requiring you to apply formulas for magnetic force, Biot-Savart Law, Ampere's Circuital Law, and galvanometer conversions. Practising all 28 with worked solutions is strongly recommended before your board exam.
Is Chapter 4 Moving Charges and Magnetism important for JEE Main?
Yes, this chapter is among the highest-weightage topics in JEE Main Physics. Expect 1–2 questions directly from this chapter every year, typically on motion of a charged particle in a magnetic field, Biot-Savart Law, and Ampere's Circuital Law. According to NTA's official JEE Main question papers from 2019 to 2024, this chapter features in almost every paper.
What is the Lorentz force formula?
The Lorentz force on a charged particle is F = qE + q(v × B), where q is the charge, E is the electric field, v is the velocity, and B is the magnetic field. The electric component acts along the field direction, while the magnetic component acts perpendicular to both the velocity and the magnetic field, so it never does work on the particle.
How do you convert a galvanometer into an ammeter or voltmeter?
To convert a galvanometer (resistance G, full-scale deflection current Ig) into an ammeter for range I, connect a shunt resistance S = Ig·G / (I − Ig) in parallel. To convert it into a voltmeter for range V, connect a series resistance R = V/Ig − G in series. These conversions are standard 3-mark CBSE board questions.
Where can I download the NCERT Solutions for Class 12 Physics Chapter 4 PDF for free?
The free PDF of NCERT Solutions for Class 12 Physics Chapter 4 is available directly on eSaral's website. No registration is needed — click the Download button on the page. The PDF includes step-by-step solutions to all 28 questions, formatted according to CBSE board exam standards. You can also access solutions for all other chapters via NCERT Solutions for Class 12 Physics.