Force on a Moving Charge: Direction, Circular Motion & Energy | A-Level Physics

Why can a magnetic field bend a moving charge without increasing its kinetic energy? Understand magnetic force, particle direction and circular motion for A-level Physics. Work through F = BQv, the angle rule, Fleming's left-hand rule and the derivation of r = mv / BQ. Then calculate a proton's force and path radius, distinguish magnetic steering from electric acceleration, and explore cyclotrons, linear accelerators, velocity selectors and the Hall effect. Useful for AQA, OCR A, Pearson Edexcel and Cambridge International revision. Application requirements differ between boards; the Hall-voltage derivation is particularly relevant to Cambridge International. Chapters 00:00 Why can a force bend without speeding up? 00:25 Magnetic force: F = BQv 00:51 Field symbols and force direction 01:43 When the magnetic force is zero 02:28 No magnetic work and circular motion 03:21 Deriving the circular radius 04:17 Worked proton calculations 05:12 Electric fields supply energy 05:37 Cyclotron motion and timing 06:42 Linear accelerators 07:13 Velocity selectors 08:14 Hall effect and Hall voltage 09:38 Recap and further practice Lesson notes: https://inklearning.co.uk/physics/mag... Practise with questions and worked answers: https://inklearning.co.uk/physics/pra... Need the circular-motion foundations? https://inklearning.co.uk/physics/per... Previous lesson — magnetic flux density and the force on a wire: https://inklearning.co.uk/physics/mag... Explore the magnetic-fields unit: https://inklearning.co.uk/physics/mag... Next lesson — magnetic flux and flux linkage: https://inklearning.co.uk/physics/mag... Try the practice questions, then explain why a force can change velocity without changing speed. Subscribe for more A-level Physics made visual. #ALevelPhysics #MagneticFields #InkPhysics