Magnetism
Study of magnetic fields, magnetic materials, and magnetic phenomena.
Class 12 — Magnetism
Forces, fields, induction, and applications
Magnetic Field
Calculate magnetic field strength, magnetic force, and magnetic flux using Ampere's Law.
Lorentz Force
Find magnetic force on a moving charge: F = |q|vB.
Force on Current Wire
Calculate F = BIL on a conductor in a magnetic field.
Ampere's Law — Straight Wire
Magnetic field B = μ₀I/(2πr) around a long wire.
Solenoid Field
Uniform field inside ideal solenoid: B = μ₀nI.
Magnetic Flux
Flux through a surface: Φ = BA cos θ.
Faraday's Induction
Induced EMF from changing flux: |ε| = N|ΔΦ/Δt|.
Torque on Current Loop
Motor torque τ = NIAB sin θ in uniform B.
Cyclotron Radius
Orbit radius r = mv/(|q|B) for charged particles.
Hall Effect
Hall voltage V_H = BI/(nqt).
Inductor Energy
Stored magnetic energy U = ½LI².
Quick practice quiz
Test your understanding — tap an option, then open the linked calculator to explore.
Lorentz force magnitude on charge q moving at speed v in field B (θ=90°):
Open calculator →Ideal solenoid field inside is approximately:
Open calculator →