| Term | Definition | Unit / Dimensional Formula |
|---|---|---|
| Magnetic Field (B) | The region around a magnet or current where magnetic forces act; defined by force on a moving charge F = qv×B | Tesla (T); [MT^{-2}$$A^{-1}] |
| Biot-Savart Law | dB = (μ_{0}/4π)(I dl sinθ/); gives magnetic field due to a current element; magnetic analog of Coulomb's law | [MT^{-2}$$A^{-1}] |
| Ampere's Circuital Law | ∮B·dl = μ_{0}I_enc; line integral of B around any closed loop equals μ_{0} × enclosed current | [MLT^{-2}$$A^{-1}] |
| Permeability of Free Space (μ_{0}) | 4π × 10^{-7} T·m/A; fundamental constant relating B to the current producing it | [MLT^{-2}$$A^{-2}] |
| Lorentz Force | F = q(E + v×B); total electromagnetic force on a charge q moving with velocity v | Newton (N); [M] |
| Magnetic Moment (M) | M = NIA for a current loop; measure of loop's tendency to align with an external field | A·; [] |
| Torque on a Current Loop | τ = NIAB sinθ = MB sinθ; torque experienced by a magnetic moment in an external field | N·m; [ML^{2}$$T^{-2}] |
| Solenoid | A long cylindrical coil with N turns and length L; creates uniform B = μ_{0}nI inside | — |
| Toroid | A donut-shaped solenoid; B = μ_{0}NI/(2πr) inside ring; B = 0 in hollow centre and outside | — |
| Cyclotron Radius | r = mv/(qB); radius of circular path of a charged particle in uniform B | m; [L] |
| Cyclotron Period | T = 2πm/(qB); time for one complete revolution; independent of speed | s; [T] |
| Magnetic Susceptibility (χ) | χ = M/H; dimensionless measure of how much a material magnetises in response to H | Dimensionless |
| Relative Permeability (μᵣ) | μᵣ = 1 + χ; ratio of material's permeability to μ_{0}; dimensionless | Dimensionless |
| Diamagnetism | χ < 0; material is weakly repelled by external field; examples: Cu, Bi, | — |
| Paramagnetism | 0 < χ << 1; material weakly attracted; obeys Curie's law χ = C/T | — |
| Ferromagnetism | χ >> 1; strongly attracted; has magnetic domains; shows hysteresis | — |
| Retentivity | Residual magnetic flux density (B) retained when external field H is reduced to zero | Tesla (T) |
| Coercivity | Magnitude of reverse H required to reduce residual B to zero; [A/m] | A/m; [A] |
Part of MAG-01 — Magnetic Effects of Current & Magnetism
Definitions Glossary — 18 Key Terms
Like these notes? Save your own copy and start studying with NoteTube's AI tools.
Sign up free to clone these notes