Force on a Moving Charge
Part of the Electricity and Magnetism section of Coddy's Physics journey. Lesson 42 of 51.
A moving charge in a field B feels
F = q v B sin θ
θ between v and B; zero when the charge moves along B.
The right-hand rule: fingers along v, curl them toward B, the thumb is the force on a positive charge. A negative charge is pushed the other way.
The force is at right angles to the motion: it turns the charge without changing its speed.
Challenge
A proton moves to the right through a magnetic field that points into the page. Set your axes, z too, then draw the magnetic force on it.
Try it yourself
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
All lessons in Electricity and Magnetism
2The Electric Field
The Electric FieldField of Several ChargesThe Uniform FieldA Charge in a Uniform FieldRecap - Stopping a Proton11Magnetic Forces
Force on a Moving ChargeCircles in a FieldForce on a WireTwo Parallel WiresRecap - Current Balance3Energy and Potential
Electric Potential EnergyElectric PotentialField and PotentialRecap - Accelerating Ions6Current and Resistance
Current and VoltageResistance and Ohm's LawSeries and ParallelElectric PowerRecap - Fairy Lights9Capacitors in Circuits
A Capacitor in a CircuitCharging a CapacitorDischarging a CapacitorRecap - Defibrillator