Class 12 Physics — Chapter 4: Moving Charges and Magnetism
90 practice questions · 30 Easy · 30 Medium · 30 Hard
Practise Class 12 Physics Chapter 4, "Moving Charges and Magnetism", with 90 NCERT-aligned multiple-choice questions. The set is split into 30 Easy, 30 Medium and 30 Hard questions, so you can warm up on the fundamentals and then push into the exam-level problems that separate top scorers in CBSE Board exams, JEE Main, JEE Advanced and NEET UG.
"Moving Charges and Magnetism" is one of the chapters where numerical problem-solving, derivations and conceptual application really pays off. Each MCQ on this chapter is timed and uses exam-grade marking (+2 correct, −1 wrong, 0 skipped), training the same accuracy-under-pressure that real papers demand. Every question carries a short explanation, so a wrong answer becomes a quick lesson rather than a dead end — the fastest way to close gaps before a test.
Use this chapter as targeted revision: attempt the Easy set first to confirm your basics on Moving Charges and Magnetism, then move to Medium and Hard to test application and problem-solving. Your accuracy, streaks and XP save automatically, and the chapter feeds into your overall Class 12 Physics mastery score. A few sample questions are shown below; sign in free to practise all 90.
Key concepts: Moving Charges and Magnetism (Class 12 Physics)
This chapter covers the magnetic force on moving charges and currents, the Biot–Savart and Ampere's laws, and devices like the solenoid and moving-coil galvanometer.
- Lorentz force
- A charge moving in a magnetic field feels F = qv×B; combined with the electric force it gives the Lorentz force.
- Force on a current
- A current-carrying conductor in a field feels F = BIL sinθ; this is the basis of motors.
- Biot–Savart law
- Gives the magnetic field of a current element; used to find the field of loops and wires.
- Ampere's circuital law
- ∮B·dl = μ₀I_enclosed; used for symmetric cases like a long wire (B = μ₀I/2πr) and a solenoid (B = μ₀nI).
- Moving-coil galvanometer
- A current-carrying coil in a field experiences a torque proportional to current; converted to ammeter (shunt) or voltmeter (series resistance).
Key formulas — Moving Charges and Magnetism
💡 Exam tips for Moving Charges and Magnetism
- The magnetic force qv×B is always perpendicular to velocity, so it does no work — only changes direction.
- Use Ampere's law for high-symmetry cases (wire, solenoid, toroid); Biot–Savart for loops and arcs.
Sample questions
Force on charge q moving with v in field B:
Lorentz force.
Field at centre of circular loop (radius R, current I):
B = μ₀I/(2R).
Field inside long solenoid (n turns/length):
Uniform field B = μ₀nI.
Moving Charges and Magnetism — FAQs
What are the key concepts in Class 12 Physics Moving Charges and Magnetism?+
This chapter covers the magnetic force on moving charges and currents, the Biot–Savart and Ampere's laws, and devices like the solenoid and moving-coil galvanometer. Key ideas include Lorentz force, Force on a current, Biot–Savart law, Ampere's circuital law, Moving-coil galvanometer.
What does Class 12 Physics Chapter 4 (Moving Charges and Magnetism) cover on XamBaaz?+
It covers 90 NCERT-aligned MCQs on "Moving Charges and Magnetism" — 30 Easy, 30 Medium and 30 Hard — each with a timed quiz and an instant explanation, suitable for CBSE Board exams, JEE Main, JEE Advanced and NEET UG.
Are these "Moving Charges and Magnetism" questions free to practise?+
Yes — sign in with Google to practise "Moving Charges and Magnetism" free. Full unlimited access is ₹999/year (limited-time launch price), with no per-chapter charges.
How should I revise "Moving Charges and Magnetism" for the exam?+
Start with the Easy quiz to confirm your fundamentals, then attempt Medium and Hard for application-level practice. Review each explanation, retry the questions you miss, and track your accuracy on this chapter until it is consistently high.
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