ᒪEᗩᖇᑎIᑎG ᒍᑌᑎᑕTIOᑎ
CBSE
CLASS 10 SCIENCE
CHAPTER 10:LIGHT REFLECTION AND REFRACTION
NOTES
1. Reflection of Light:
👉When light falls on a smooth and shiny surface, it bounces back in a predictable manner, which is known as reflection.
👉The laws of reflection state that the incident ray, reflected ray, and normal at the point of incidence, all lie in the same plane.
👉The angle of incidence is equal to the angle of reflection.
2. Image Formation by Plane Mirrors:
👉A plane mirror is a flat, smooth surface that reflects light according to the laws of reflection.
👉The image formed by a plane mirror is virtual, erect, and of the same size as the object.
👉The distance of the image from the mirror is equal to the distance of the object from the mirror.
3. Spherical Mirrors:
👉Spherical mirrors have curved surfaces. They are of two types: concave and convex mirrors.
👉Concave mirrors are thicker at the center and thinner at the edges. They converge light rays.
👉Convex mirrors are thinner at the center and thicker at the edges. They diverge light rays.
4. Image Formation by Spherical Mirrors:
👉The image formed by a concave mirror can be real or virtual, depending on the position of the object.
👉The image formed by a convex mirror is always virtual, erect, and smaller in size than the object.
5. Sign Convention for Spherical Mirrors:
👉In the case of spherical mirrors, a simple sign convention is followed:
👉Distances parallel to the principal axis are measured from the pole (P) of the mirror.
👉Distances above the principal axis are considered positive, and those below are considered negative.
👉Distances to the right of the origin are positive, and those to the left are negative.
6. Refraction of Light:
👉Refraction is the bending of light when it passes from one medium to another of different optical density.
👉The amount of bending depends on the speed of light in different media.
👉The refractive index (n) of a medium is the ratio of the speed of light in vacuum to the speed of light in that medium.
7. Laws of Refraction:
👉The incident ray, refracted ray, and normal at the point of incidence all lie in the same plane.
👉Snell's law states that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant, which is the refractive index of the medium.
8. Refraction through a Rectangular Glass Slab:
👉When light passes through a rectangular glass slab, it undergoes refraction at both the surfaces and emerges parallel to the incident ray but displaced from its original path.
9. Refraction by Spherical Lenses:
👉Spherical lenses have curved surfaces and are of two types: converging (convex) and diverging (concave) lenses.
👉Converging lenses converge or focus light rays.
👉Diverging lenses diverge light rays.
10. Image Formation by Lenses:
👉The image formed by a converging lens can be real or virtual, depending on the position of the object.
👉The image formed by a diverging lens is always virtual, erect, and smaller in size than the object.
⭐These are the key points and notes from Chapter 10 of the CBSE Class 10 NCERT Science textbook. Make sure to refer to your textbook for a more comprehensive understanding of the concepts and to study the diagrams and examples provided.
