Concept 2 of 9Foundation
Watch on YouTubeVideoLight travels in straight lines
In a uniform medium, light travels in perfectly straight lines called rays.
Classic proof: arrange 3 cards with pinholes. A torch light passes through to your eye ONLY when all 3 holes are in a perfect straight line. Tilt one card — light doesn't reach you.
This is also why we see sharp shadows, and why we can draw "line-of-sight" in geometry.
Example
Laser pointer beam in dusty air looks like a pencil-thin straight line. That's rectilinear propagation.
💡 Tip:Light only bends at mirrors (reflection) or at boundaries between media (refraction).
▶Prefer a video? Open YouTube search for “rectilinear propagation of light class 6”↗🎯 Try it!
5 questions to check what you just read.
0 / 5
- Q1.Light travels in:
- Q2.Three cards with pinholes: light passes through ONLY when holes are:
- Q3.Shadows form because light:
- Q4.Light rays in a dusty room look like:
- Q5.Which is a real example of light going straight?