Complete notes for Chapter 10 Electromagnetism. Includes Force on Current-Carrying Conductor, Magnetic Flux, Faraday's Law, Lenz's Law, Velocity Selector, Ferrofluids, and Seismometer.
Force (F): A conductor of length L carrying current I placed in a uniform magnetic field B experiences a force given by F = ILB sinθ. Direction is given by Fleming's Left-Hand Rule or Right-Hand Rule.
Maximum Force: When conductor is perpendicular to the field (θ = 90°).
Magnetic Flux (Φ): Total magnetic field lines passing through an area. Φ = B · A = BA cosθ. Unit: Weber (Wb).
Magnetic Flux Density (B): Flux per unit area (B = Φ/A). Also called Magnetic Induction. Unit: Tesla (T) or Wb m⁻².
Force (Lorenz Force): F = q(v x B). Magnitude F = qvB sinθ.
Path: If v is perpendicular to B, the path is circular with radius r = mv/qB. If v is parallel, path is straight (no force).
Velocity Selector: Uses crossed electric and magnetic fields to select particles of a specific velocity (v = E/B) where electric and magnetic forces balance.
Faraday's Law: The induced EMF is directly proportional to the rate of change of magnetic flux (ε = -N ΔΦ/Δt).
Lenz's Law: The direction of induced current is such that it opposes the change in flux that acts as its cause. It is a manifestation of Conservation of Energy.
The EMF induced by the motion of a conductor across a magnetic field. ε = vBL sinθ.
Definition: Liquids containing suspended magnetic nanoparticles (like iron oxide) that become strongly magnetized in a magnetic field.
Applications: Cooling in loudspeakers, rotary seals in hard drives, targeted drug delivery, and MRI contrast agents.
An instrument that detects ground motion (earthquakes) using electromagnetic induction. Relative motion between a suspended magnet and a fixed coil induces an EMF proportional to the velocity of ground motion.