JEE Physics Moving Charges and Magnetism is a core chapter in Class 12 Physics that explores how moving charges interact with magnetic fields and the magnetic effects of current. This chapter is crucial for understanding electrodynamics, a key area frequently tested in JEE Main & Advanced exams.

The chapter bridges the concepts of electric charges in motion and magnetic fields, helping students understand Lorentz force, motion of charged particles, and applications in electromagnets, cyclotrons, and magnetic devices.

Studentbro.in’s Moving Charges and Magnetism content provides step-by-step explanations, derivations, formulas, and JEE-oriented numerical problems, making the topic easier to grasp and apply.

Direct Links to Download 2025-26 JEE Physics Notes (PDF)

► Click “Download Here” next to your access the free PDF.

♦ Moving Charges And Magnetism ⇒ Download Here

♦ Maths in Physics ⇒ Download Here

♦ Units And Measurements ⇒ Download Here

♦ Motion In A Straight Line ⇒ Download Here

♦ Motion In A Plane ⇒ Download Here

♦ Laws Of Motion ⇒ Download Here

♦ Friction ⇒ Download Here

♦ Work, Energy And Power ⇒ Download Here

♦ System of Particles And Rotational Motion ⇒ Download Here

♦ Gravitation ⇒ Download Here

♦ Kinetic Theory ⇒ Download Here

♦ Thermal Properties Of Matter ⇒ Download Here

♦ Thermodynamics ⇒ Download Here

♦ Transmission of Heat ⇒ Download Here

♦ Oscillations ⇒ Download Here

♦ Waves ⇒ Download Here

♦ Current Electricity ⇒ Download Here

♦ Electrostatic Potential And Capacitance ⇒ Download Here

♦ EMI & AC ⇒ Download Here

♦ Mechanical Properties of Fluids ⇒ Download Here

♦ Dual Nature of Radiation And Matter ⇒ Download Here

♦ Wave Optics ⇒ Download Here

♦ Physics Formula PDF for Entrance Exam ⇒ Download Here

Overview of Moving Charges and Magnetism

The chapter covers:

• Magnetic field due to a moving charge

• Magnetic field due to current-carrying conductors

• Biot-Savart Law and Ampere’s Circuital Law

• Lorentz force on moving charges

• Motion of charged particles in uniform magnetic fields

• Force on a current-carrying conductor in a magnetic field

• Magnetic dipole moment and torque

• Applications in devices like cyclotrons, mass spectrometers, and galvanometers

• JEE Main & Advanced numerical problems

This chapter forms a foundation for understanding magnetic effects of currents and applications in electromagnetism.

Importance of Moving Charges and Magnetism for JEE

• High weightage in Class 12 Physics

• Questions are both conceptual and numerical

• Helps understand magnetic fields, force on moving charges, and magnetic devices

• Develops analytical and vector problem-solving skills

• Essential for engineering, electronics, and physics applications

Magnetic Field due to Moving Charges

• A moving charge produces a magnetic field around its path.

• Biot-Savart Law describes the magnetic field due to a small segment of current:

dB=μ04πIdl×r^r2d\mathbf{B} = \frac{\mu_0}{4\pi} \frac{I d\mathbf{l} \times \mathbf{\hat{r}}}{r^2} dB=4πμ0​​r2Idl×r^​

• Magnetic field of a long straight wire:

B=μ0I2πrB = \frac{\mu_0 I}{2 \pi r} B=2πrμ0​I​

• Solenoids and circular loops: Magnetic field along the axis can be calculated using Biot-Savart Law.

Applications: Electromagnets, solenoids, and magnetic coils used in JEE numericals.

Lorentz Force on Moving Charges

• A charged particle moving in a magnetic field experiences a force:

F=q(v×B)\mathbf{F} = q (\mathbf{v} \times \mathbf{B}) F=q(v×B)

• Direction is given by right-hand rule.

• Motion can be:

  • Circular or helical in a uniform magnetic field

  • Deflection in mass spectrometer

Force on a Current-Carrying Conductor

• Current-carrying conductor in a magnetic field experiences a force:

F=BILsin⁡θF = B I L \sin \theta F=BILsinθ

where LLL = length of conductor in magnetic field, III = current, θ\thetaθ = angle between BBB and LLL

• Basis for motors, galvanometers, and electromechanical devices

Ampere’s Circuital Law

• Relates magnetic field around a closed loop to current passing through the loop:

∮B⋅dl=μ0Ienclosed\oint \mathbf{B} \cdot d\mathbf{l} = \mu_0 I_{\text{enclosed}} ∮B⋅dl=μ0​Ienclosed​

• Applications: magnetic field of solenoid and toroid

Motion of Charged Particles in Uniform Magnetic Fields

• Velocity perpendicular to magnetic field: Circular motion with radius:

r=mvqBr = \frac{mv}{qB} r=qBmv​

• Velocity at an angle to magnetic field: Helical motion

• Applications in cyclotron, mass spectrometer, and magnetic confinement devices

Magnetic Dipole Moment and Torque

• Magnetic dipole moment of a current loop:

m=IA\mathbf{m} = I \mathbf{A} m=IA

• Torque on a magnetic dipole in a uniform magnetic field:

τ=m×B\tau = \mathbf{m} \times \mathbf{B} τ=m×B

• Explains orientation of current loops in magnetic fields, galvanometers, and meters

Stepwise Problem-Solving Approach

1. Identify type of magnetic problem (moving charge, current, conductor, solenoid)

2. Write known quantities (q,v,B,I,L,θq, v, B, I, L, \thetaq,v,B,I,L,θ)

3. Apply appropriate formulas for Lorentz force, Biot-Savart Law, or Ampere’s Law

4. Solve step by step, paying attention to direction

5. Verify units, magnitudes, and physical meaning

Numerical Problems in Moving Charges and Magnetism

JEE numericals often include:

• Force on moving charges in magnetic fields

• Radius of circular motion in magnetic fields

• Torque on current loops

• Magnetic field due to wires, solenoids, and circular loops

• Motion of charged particles in cyclotrons or spectrometers

Daily practice strengthens accuracy, vector calculations, and conceptual clarity.

Why Daily Practice is Important

• Reinforces concepts of moving charges and magnetic interactions

• Improves numerical problem-solving skills

• Helps understand applications of magnetic fields in devices

• Reduces mistakes in exam situations

Who Should Study Moving Charges and Magnetism

• JEE Main & Advanced aspirants

• Class 12 Physics students

• Students preparing for engineering, electronics, and physics exams

• Anyone aiming to master magnetic effects of currents and particle motion

How to Study Moving Charges and Magnetism Effectively

1. Understand Lorentz force, Biot-Savart Law, and Ampere’s Law

2. Memorize formulas for magnetic field, force, torque, and circular motion radius

3. Practice numerical problems of charged particles in magnetic fields

4. Learn vector directions with right-hand rules

5. Revise applications of solenoids, coils, and galvanometers

Benefits of StudentBro.in Moving Charges and Magnetism Content

• Fully aligned with latest JEE syllabus

• Prepared by expert Physics educators

• Includes exam-oriented numericals, derivations, and diagrams

• Clear explanations for easy understanding

• Ideal for revision and concept mastery

Conclusion

JEE Physics Moving Charges and Magnetism is a vital chapter covering magnetic fields, Lorentz force, Biot-Savart Law, Ampere’s Law, motion of charged particles, and torque on current loops. Mastery of these concepts ensures confidence in JEE Main & Advanced exams.

Studentbro.in’s resources provide structured explanations, numerical practice, and diagrams, helping students excel in competitive exams.

Prepare with Moving Charges and Magnetism by StudentBro to strengthen your foundation in magnetism and enhance problem-solving skills for JEE.