Physics · Class 12 · Chapter 4
Moving Charges and Magnetism
12 lessons 101 min 2 simulations
This chapter shows that moving charges both make magnetic fields and feel them. It sets out the Lorentz force and the force on a wire, follows charges round circles and helices in a uniform field, builds fields from currents with the Biot–Savart law and Ampere's circuital law (loop, straight wire, solenoid), and ends with forces between wires, the torque on a coil, the loop as a magnetic dipole and the moving coil galvanometer.
What the exam asks
NEET asks for the radius, period and pitch of charged particles in a field, the direction of the force by the right-hand rule, and fields of a wire, loop, arc and solenoid, often combined by superposition. Force per metre between parallel wires, torque on a coil and galvanometer conversion to ammeter or voltmeter are regular. Marks are lost on sign for electrons, on mixing up μ₀I/2πr with μ₀I/2R, and on measuring θ from the wrong line.
Lessons
12 lessons · 101 min
1Magnetic field and the Lorentz forceNCERT §4.1, §4.2.1, §4.2.27 min2Force on a current-carrying conductorNCERT §4.2.36 min3Motion in a magnetic fieldNCERT §4.311 min 1 sim4Biot–Savart lawNCERT §4.47 min5Field on the axis of a circular loopNCERT §4.57 min6Ampere's circuital lawNCERT §4.67 min7The solenoidNCERT §4.76 min8Force between parallel currentsNCERT §4.87 min9Torque on a current loopNCERT §4.9.17 min10Current loop as a magnetic dipoleNCERT §4.9.27 min11The moving coil galvanometerNCERT §4.1011 min 1 sim12Chapter reviewMust-know facts, traps and formulas18 min