Moving Charges and Magnetism

📋 Course Outline

1. Magnetic Force and Particle Motion
2. Forces on Current-Carrying Conductors
3. Magnetic Fields from Currents
4. Loops, Solenoids, and Ampere Law
5. Galvanometer and Its Conversions

📖 1. Magnetic Force and Particle Motion

📝 Essential Points

📐 Formula — The magnetic force on a charged particle is $F=qvB\sin\theta$, where θ is the angle between velocity and magnetic field.

📐 Formula — In a uniform magnetic field, magnetic force supplies the centripetal force according to $qvB=\frac{mv^2}{r}$.

📐 Formula — The radius, time period, and frequency of a charged particle moving in a circular path are $r=\frac{mv}{qB}$, $T=\frac{2\pi m}{qB}$, and $f=\frac{qB}{2\pi m}$, respectively.

• When the velocity is perpendicular to the magnetic field, the magnetic force is $F=qvB$ and is perpendicular to both the velocity and the magnetic field.

💡 Memory Hook

Magnetic force ⟂ velocity → circular motion

📖 2. Forces on Current-Carrying Conductors

📐 Formula — The force on a straight current-carrying conductor in a magnetic field is $F=BIl\sin\theta$.