Science · Class 8
Light
Laws of reflection, multiple images, and human eye defects.
4 sections15–25 min read6 MCQs · 2 examples
Chapter Overview
Light enables vision when reflected from objects into our eyes. This chapter covers laws of reflection, regular and diffused reflection, multiple images in plane mirrors, and structure of human eye.
Laws of Reflection
- Incident ray, reflected ray, and normal lie in same plane
- Angle of incidence = angle of reflection
- Regular reflection: smooth surface (mirror)
- Diffused reflection: rough surface — see non-luminous objects
Multiple Images
- Two mirrors at angle create multiple images
- Kaleidoscope: 3 mirrors at 60° — beautiful patterns
- Periscope: two parallel mirrors in tube
Human Eye
- Cornea, iris (controls pupil), lens, retina (rods and cones)
- Blind spot: no photoreceptors
- Visually impaired: Braille, assistive technology
Solved Examples
Step-by-step solutions — read each step before checking the final answer.
Laws of reflection
State two laws of reflection.
- 1i = r (angles equal)
- 2Rays and normal in same plane
- 3Applies to all surfaces
Answer
Angle of incidence = angle of reflection; coplanar rays
Kaleidoscope
How does kaleidoscope work?
- 13 plane mirrors at 60° in tube
- 2Multiple reflections create symmetrical patterns
- 3Coloured pieces reflect repeatedly
Answer
Repeated reflections in inclined mirrors
Key Points to Remember
- ✓ Braille: raised dot patterns for reading
- ✓ Persistence of vision ~1/16 second
- ✓ Concave lens for myopia; convex for hypermetropia
Exam Tips
- • Draw ray diagram for plane mirror
- • Explain Braille system
- • How does periscope work?
Practice MCQs — Light
Test your understanding with topic-wise multiple choice questions. Explanations appear after each answer.
Question 1 of 6Score: 0/0
Angle of incidence equals: