Light Travels in a Straight Line:
There is a well-known principle in physics called the principle of rectilinear propagation of light, which states that light travels in a straight line. This means that when light travels through a medium or in a vacuum, it does not deviate from its path unless it encounters an obstacle or is refracted or reflected.

Explanation:
- Light is a form of electromagnetic radiation that consists of photons. These photons travel in straight lines from the source of light to the object it illuminates or reflects off.
- This straight-line path of light is due to the fact that light travels at a constant speed in a homogeneous medium. When light enters a different medium or encounters an obstacle, it may change direction due to refraction or reflection, but it still follows the principle of traveling in a straight line.
- The straight-line path of light is the reason why we see shadows forming when an object blocks the path of light. The light rays that were originally traveling in a straight line are blocked by the object, creating a shadow on the other side.
- This principle is essential in various applications of optics, such as in the design of lenses, mirrors, and other optical instruments. Understanding that light travels in a straight line helps scientists and engineers create accurate models and designs for these devices.
Therefore, based on the principle of rectilinear propagation of light and the behavior of light in various mediums, we can confidently say that light travels in a straight line.

Light travels in a Straight line.