Topic 17: Electromagnetic Forces

Vocabulary-style flashcards covering definitions, key physicists, units, and physical rules from the Electromagnetic Forces lecture notes.

Magnetic field

A region of space where a magnetic north pole (or a current-carrying conductor, or a moving charged particle) experiences a magnetic force.

Gravitational field

A region of space where a mass experiences a gravitational force.

Electric field

A region of space where an electric charge experiences an electrical force.

Magnetic field lines

Vector quantities representing the direction a north pole of a free compass needle would point; they leave the north pole and enter the south pole of a magnet.

Magnetic flux density ($B$)

The force acting per unit current per unit length on a conductor placed perpendicular to the magnetic field.

Current balance

A device that uses the principle of moments to measure the magnetic flux density of a field based on the magnetic force acting on a current-carrying conductor.

Velocity selector

A device that uses perpendicular (crossed) electric and magnetic fields to allow only charged particles moving at a specific velocity ($v = \frac{E}{B}$) to pass through undeflected.

Helical path

The spiral trajectory followed by a charged particle when it enters a uniform magnetic field at an angle ($\theta$) between $0^{\circ}$ and $90^{\circ}$.

Standard value for Earth’s surface magnetic field

$5 \times 10^{-5}\,T$.

Pitch of the helix

The distance, measured along the axis, between two successive turns of a helical path.