Velocity

In the context of electromagnetic waves, velocity describes the rate of wave propagation, accounting for both magnitude (speed) and direction.

• • As a vector quantity, velocity provides a full description of the wave’s displacement over time, indicating how fast and in which direction it moves.
  • Velocity can be positive or negative, representing motion in different directions, and is measured in units such as meters per second (m/s), kilometres per hour (km/h), or miles per hour (mph), with an indication of direction.
• In contrast, speed refers only to the magnitude of motion—how fast the wave travels—without regard to direction.
  • It is the magnitude of the displacement of an object per unit of time.
  • Speed does not consider the direction of motion, only the rate at which an object moves.
  • Speed is always positive or zero, representing the magnitude of motion.
  • Speed is measured in units such as meters per second (m/s), kilometres per hour (km/h), or miles per hour (mph).
• Direction in the context of velocity is typically quantified by angles or coordinates relative to a reference point or axis.
  • For electromagnetic waves, this could be described using angles (e.g., degrees or radians) from a defined direction (such as the horizontal or vertical axis in a plane) or by using a coordinate system (such as Cartesian or polar coordinates) to specify the precise direction of wave propagation.