A ray of light (light ray or just ray) is a common term when talking about optics and electromagnetism.
- A ray of light is a way of imagining, conceptualising and representing the way light moves.
- The idea of a ray of light is rooted in the observation that light travels in straight lines until it meets an obstacle.
- It is common sense to think of a narrow beam of light as being composed of parallel arrows or a bundle of rays.
- The bundle of rays can then be used to trace what happens when light strikes a complex object such as a lens or convex mirror.
- Single rays are often used to plot the path of a specific wavelength of light and compare it with the path of others.