Chapter 9 · Physics
Light Travels in Straight Lines
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You can hear a friend round a corner but not see them: sound bends, light travels in straight lines. We draw its path as a ray.
Download the short notesPDF, 113 KB · solved examples, practice set and answer key Download the workbook
PDF, 170 KB · fill in the blanks, true/false, assertion-reason, MCQ, numericals, short answer, match the columns; detailed solutions at the end Up next in this chapter
Reflection of LightThe Moon makes no light, yet it shines at night: sunlight bounces off it to our eyes. That bouncing back is reflection.Physics
Key points
- In a uniform medium light travels in straight lines.
- Ray = path + direction (an arrow); beam = many rays.
- Sharp shadows and the 3-card test are the evidence.
- Sound (wavelength ~1 m) bends round corners; light (< 0.001 mm) practically does not.
The 3-card test
Sharp shadows
The ray model works for everyday sizes because light's wavelength is tiny; it is a model, not the whole story.
Quick quiz
4 questions. Choose an answer for each, then submit to see your score and the explanations.
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