magnetism — Jemoka Knowledge Base

For a charge to do something in a magnetic field, it has to have velocity; nothing happens without movement. So:

\begin{equation} \vec{F}_{M} = q \vec{v} \times \vec{B} \end{equation}

To calculate: magnitude: qvB \sin \theta + right hand rule. Radius You maybe asked to find the radius of the path the particle takes, so:

\begin{equation} \frac{v^{2}}{r} = a \end{equation}

So, the net force here is:

\begin{equation} qvB = Ma \end{equation}

So plug in and solve Current along a wire \begin{equation} \vec{F} = \int I \dd{l} \times \vec{B} \end{equation} The sum of the current across the wire is the same as q \vec{v}. This equals IlB \sin \theta in magnitude for constant current. “FILB - sintheta” Induced magnetic field For the induced magnetic field of a current, use the curvey (curl) right hand rule. The actual magnitude induced by the wire is ampere’s law:

\begin{equation} \oint \vec{B} \cdot \dd{\vec{l}} = \mu I \end{equation}

where, u_0 is vacuum permeability (4 \pi \times 10^{-7} \frac{T \cdot m}{A}). Magnetic Field of a Solenoid \begin{equation} Bs = \mu_{0} n I \end{equation} where, n = \frac{N}{L}, the number of turns of the solenoid per length. Magnetic Field of a Loop \begin{equation} B 2\pi r = \mu_{0} I \end{equation} where, the surface integral of length of a loop is just the circumference WIRES ARE OPPOSITE Current’s induced magnetic fields in the same direction attracts, and in opposite directinos repel Full description of magnetic field non-bdl-b For instance, current in a loop and desire magnetic field in the center