Question

How does light travel in a straight line ?

Answer 1

To answer this question, we first need to understand what is light. Light, often known as visible light, is electromagnetic radiation that falls within the region of the electromagnetic spectrum that the human eye can perceive. Between the infrared and ultraviolet, visible light is characterized as having wavelengths in the range of 400–700 nanometers.

Complete answer:
Diffraction: Diffraction is a term that describes a variety of phenomena that occur when a wave collides with an obstruction or an opening. It's described as the bending of waves around the corners of an obstruction or through an aperture into the region of the obstacle's geometrical shadow. The diffracting item or aperture effectively becomes the propagating wave's secondary source. In 1660, Italian scientist Francesco Maria Grimaldi created the term "diffraction" and was the first to observe the phenomenon accurately.

So, we conclude that the fact that light is a wave causes it to travel in straight lines. When light strikes specific obstructions, though, it might vary its route (away from a straight line). Diffraction is a term used to describe this phenomenon. Because diffraction is such a little effect, light is considered to move in a straight line.

Note: Dispersion is a phenomenon in optics where the phase velocity of a wave is affected by its frequency. Dispersive media are those that have this trait in common. For specificity, the phrase chromatic dispersion is also employed. Although the term is most commonly associated with light and other electromagnetic waves, it can also refer to any type of wave motion, including acoustic dispersion.