Magnetic Field
Magnetic flux density, terrestrial magnetism, Lorentz magnetic force, Hall effect, conductor and parallel wire interactions, moving-coil galvanometer, Biot-Savart and Ampere’s laws, and solenoids.
Magnetic Field — Lessons (7)
Magnetic Fields & Terrestrial Magnetism
Magnetic flux Φ and flux density B = Φ/A (Tesla), magnetic field line geometry, neutral points between interacting fields, and Earth’s magnetic field elements (declination, inclination/dip, horizontal and vertical components).
Forces on Moving Charges & Hall Effect
Lorentz magnetic force F = q(v × B), circular and helical trajectories in uniform B-fields, cyclotron radius r = mv/(qB) and frequency, velocity selector v = E/B, J.J. Thomson’s e/m experiment, and the Hall effect V_H = BI/(nqt).
Forces on Conductors & Parallel Wires
Magnetic force on current-carrying conductors F = BIl sin θ, mutual force between parallel current-carrying wires F/l = (μ₀ I₁ I₂)/(2πd), attraction and repulsion criteria, the SI definition of the Ampere, and current balances.
Torque on Coils & Moving-Coil Galvanometer
Torque on rectangular current loops τ = BINA sin θ, magnetic dipole moment m = NIA, moving-coil galvanometer construction (radial field, soft iron core, hairsprings), current sensitivity S_I = (BAN)/C, ammeter shunt resistance, and voltmeter multiplier resistance.
Current-Generated Fields & Solenoids
Biot-Savart law dB = (μ₀/4π)(I dl sin θ)/r², Ampere’s Circuital Law ∮ B · dl = μ₀ I_enc, magnetic field around long straight wires B = μ₀I/(2πr), circular coil centers B = μ₀NI/(2r), long solenoids B = μ₀nI, and toroids.
Magnetic Field & Galvanometer Simulation Lab
60fps interactive laboratory featuring charged particle cyclotron trajectories (cyclotron radius, helical pitch, velocity filtering) and a virtual moving-coil galvanometer with radial field dynamics and live ammeter/voltmeter conversion calculators.
Unit 7 Comprehensive Assessment
20-question summative exam covering all 3 syllabus competencies (7.1 to 7.3) with automated grading, competency breakdown, and targeted revision links.