Class 8 Science Chapter 10 PPT – Light: Mirrors and Lenses | USP

Class 8 Science Chapter 10 – Light: Mirrors and Lenses

Free notes, PPT, and worksheets for Class 8 Science Chapter 10, based on the new NCERT syllabus (Session 2026–27). This chapter explains how mirrors and lenses form images, and why we see reflections and magnified views the way we do — covering Spherical Mirrors, Characteristics of Images, Laws of Reflection, and Lenses, with real-life examples students can relate to.

What Are Spherical Mirrors?

Spherical mirrors are curved mirrors that form part of a hollow sphere. They are of two main types:

• Concave mirror — curves inward, like the inside of a spoon. It can converge (bring together) light rays, and is used in torches, headlights, and shaving/makeup mirrors.
• Convex mirror — curves outward, like the back of a spoon. It always spreads out (diverges) light rays, giving a wider field of view, which is why it is used in vehicle side-mirrors and security mirrors in shops.

Characteristics of Images Formed by Spherical Mirrors

The type of image formed depends on the mirror and the object's distance from it:

What Are the Laws of Reflection?

Whenever light bounces off any surface — flat or curved — it follows two fixed rules:

1. The angle of incidence is always equal to the angle of reflection.
2. The incident ray, the reflected ray, and the normal (an imaginary perpendicular line at the point of reflection) all lie in the same plane.

These laws apply to plane mirrors as well as spherical mirrors, and explain why a mirror image appears exactly where it does.

What Is a Lens?

A lens is a transparent object, usually made of glass or plastic, bounded by one or two curved surfaces that bend (refract) light passing through it.

• Convex lens — thicker at the middle, converges light rays to a point. Used in magnifying glasses, cameras, and to correct long-sightedness in spectacles.
• Concave lens — thinner at the middle, diverges light rays. Used to correct short-sightedness in spectacles.

Real-Life Applications

Mirrors and lenses are used all around us — car and bike rear-view mirrors (convex), dentist's examination mirrors (concave), torches and vehicle headlights (concave), spectacles for vision correction (convex and concave lenses), cameras, microscopes, and telescopes.

Frequently Asked Questions

Q1. What is the main difference between a concave and a convex mirror?
A concave mirror curves inward and can form both real and virtual images depending on the object's distance, while a convex mirror curves outward and always forms a virtual, diminished image.

Q2. Why are convex mirrors used as vehicle side mirrors?
Convex mirrors give a wider field of view than flat mirrors, allowing drivers to see more of the road behind and beside the vehicle, which improves safety.

Q3. What is the difference between a real image and a virtual image?
A real image can be formed on a screen and is usually inverted, while a virtual image cannot be formed on a screen, appears upright, and is seen only by looking into the mirror or lens.

Q4. Why do concave lenses help correct short-sightedness?
Concave lenses diverge light rays before they enter the eye, which shifts the focal point back onto the retina, correcting blurred distance vision.

Q5. What are the two laws of reflection?
First, the angle of incidence equals the angle of reflection. Second, the incident ray, reflected ray, and the normal all lie in the same plane.

What's Included in This Free Download

• 83-slide PPT covering the complete chapter with diagrams and real-life examples
• Complete notes based on the new NCERT 2026–27 syllabus
• Practice worksheet with important questions

Prepared by Sumeet Sahu, Unique Study Point, Indore. Free for all Class 8 CBSE students.