Step 1: Understanding the Concept:
This question refers to a fundamental property of light propagation. The principle is known as the rectilinear propagation of light.
Step 2: Detailed Explanation:
The principle of rectilinear propagation of light states that in a homogeneous and transparent medium, light travels along a straight-line path. This is why we cannot see around corners and why opaque objects cast sharp shadows. While light can travel in any direction from its source, the path it takes in a uniform medium is always a straight line.
Step 3: Final Answer:
Light rays travel in a straight line in a uniform medium.