Electrostatics and Electrodynamics: Key Concepts for Radiography

Electrostatics

The study of fixed or stationary charges which includes the process of electrification.

Electrification

The process of adding or subtracting electron charges from an object via friction, contact, or induction.

Friction

A method of electrification where objects are rubbed together, e.g., balloon against hair.

Contact

A method of electrification involving touching, e.g., static discharge on a radiograph.

Induction

A method of electrification that occurs without contact, important for devices like the induction motor in vacuum x-ray tubes.

Coulomb

The fundamental unit of electric charge.

1 Coulomb

Equivalent to 6.24 x 10^18 electron charges.

Laws of Electrostatics

Principles governing electric charges, including Repulsion-Attraction, Distribution, Concentration, and Movement.

Repulsion-Attraction

Opposites attract, like charges repel.

Distribution

Charges reside on the external surfaces of conductors and are distributed throughout nonconductors.

Concentration

The greatest concentration of charge (e-) will be on the surfaces where the curvature is the sharpest.

Movement

Only negative charges move along solid conductors.

Coulomb's Law

Measures the magnitude of electrostatic force and the effect distance has on attraction or repulsion.

Fixed or stationary charges

Charges that do not move, as opposed to electrical charges in motion.

Electrical charges in motion

Charges that are actively moving, unlike fixed or stationary charges.

Induction motor

A type of electronic device found in radiography that utilizes the method of induction for electrification.

True or False: The electron is the smallest unit of electric charge but is too small to be useful.

True.

True or False: Only negative charges move along solid conductors.

True.