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Light travels in straight lines in a uniform medium and allows objects to be seen when it reaches our eyes. Reflection produces images in mirrors, while multiple reflections explain devices such as periscopes and kaleidoscopes. The eye is a sensitive organ that needs protection from injury and excessive glare.
Learning Objectives
- •Explain reflection
- •Explain images in mirrors
- •Explain vision and care
Key Concepts
Reflection
Light changes direction when it strikes a reflecting surface; the angle of incidence equals the angle of reflection for a plane surface.
Images in mirrors
A plane mirror forms an upright, virtual image with predictable size and lateral inversion.
Vision and care
The cornea, lens, retina, and optic nerve work together to detect light, while adequate lighting and safe screen habits protect vision.
Terminology
Historical Insight
Periscope
Two plane mirrors can redirect light so an observer sees over an obstacle.
Kaleidoscope
Repeated reflections create patterns, showing how mirror arrangement changes the image.
Quick Check
What is regular reflection?
Why does a plane mirror show lateral inversion?
How can eyes be protected?
How to use this lesson
Read the overview first, then explain the main idea in your own words before checking the key concepts. Use the quick-check questions without looking at the answer. For examination preparation, verify dates, definitions, and syllabus requirements against your official textbook and school or examination-board guidance.