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[PDF] Download Revision Notes for Class 8 Science Chapter 16 Light
Here we are providing revision notes for class 8 science. We have two types of revision notes for class 8 science (i) Short revision notes (ii) Detailed revision notes. In this article, we are covering short revision notes for CBSE class 8 science Chapter 16 Light.
Light Class 8 Revision Notes
Light: The natural agent that stimulates sight and makes things visible. Light is reflected from all surfaces. It is a form of energy.
Objects that give out light on their own are called luminous objects. Objects that do not give out light on their own are called non-luminous objects. They just reflect light that falls on them. When light reflected from an object enters into our eyes, the object becomes visible to us.
Reflection of Light: Bouncing back of light after striking a shiny or polished surface, in the same medium, is called reflection.
Types of Reflection:
(i) Regular Reflection: When a beam of parallel light rays is incident on a smooth and plane surface, the reflected rays will also be parallel. This type of reflection is called Regular Reflection. The reflection from a plane mirror is an example of regular reflection.
(ii) Diffused or Irregular Reflection: When light is incident upon a rough or uneven surface, it is reflected in many directions due to presence of irregularities on that surface.
If a reflected light ray is reflected again on being incident on another surface, it is termed multiple reflections. Multiple reflections are used in periscopes. Periscopes are used in submarines, war tanks and by soldiers in bunkers to see objects that are not visible directly. In a kaleidoscope, beautiful patterns are formed due to multiple reflections.
Laws of reflection
- The angle of incidence is equal to the angle of reflection.
- Incident ray, reflected ray and the normal drawn at the point of incidence to the reflecting surface, lie in the same plane.
Lateral inversion is the effect produced by a plane mirror in reversing images from left to right. For e.g., our left hand will appear as right and vice versa.
The image formed by a plane mirror is:
- of the same size as that of the object
- left-right inverted
- erect and virtual
- formed behind the mirror at the same distance as the distance of the object in front of the mirror
Two mirrors inclined to each other give multiple images.
Sunlight, called white light, consists of seven colours.
Splitting of light into its constituent colours is known as dispersion.
A normal eye can see nearby and distant objects clearly.
Visually challenged persons can read and write using Braille system.
Visually challenged persons develop their other senses more sharply to improve their interaction with their environment.
Parts of Human Eye:
(i) Cornea: Transparent bulge on the front surface of the eyeball which protects the eye and helps in refraction of light.
(ii) Iris: Coloured diaphragm behind the cornea which controls the amount of light entering the eye.
(iii) Pupil: Dark hole in the middle of iris through which light enters the eye.
(iv) Eye lens: Transparent, crystalline structure behind pupil and iris.
(v) Ciliary muscles: Hole the eye lens in position and control the focal length of the eye lens.
(vi) Retina: Surface of the rear part of the eyeball where the light entering the eye is focused.
(vii) Rods and Cones: Rod cells respond to the brightness of light while cone cells respond to colours.
(viii) Blind spot: It is the least sensitive point where no rods and cones are present.
(ix) The space between the cornea and the eye lens is filled with aqueous humour.
(x) The space between the eye lens and the retina is filled with vitreous humour.
Chapter List
Chapter 1 Crop Production and Management
Chapter 2 Microorganisms: Friend and Foe
Chapter 3 Synthetic Fibres and Plastics
Chapter 4 Materials: Metals and Non-Metals
Chapter 5 Coal and Petroleum
Chapter 6 Combustion and Flame
Chapter 7 Conservation of Plants and Animals
Chapter 8 Cell Structure and Functions
Chapter 9 Reproduction in Animals
Chapter 10 Reaching the Age of Adolescence
Chapter 11 Force and Pressure
Chapter 12 Friction
Chapter 13 Sound
Chapter 14 Chemical Effects of Electric Current
Chapter 15 Some Natural Phenomena
Chapter 16 Light
Chapter 17 Stars and the Solar System
Chapter 18 Pollution of Air and Water
Benefits of Using One Page Revision Notes for Class 8 Science
Here are the benefits of using one-page revision notes for CBSE Class 8 Science:
- Concise Overview: One-page revision notes condense important information from each chapter into a single page, providing a quick and comprehensive overview of the entire syllabus.
- Time-Saving: These notes save valuable study time as they allow students to quickly review key concepts without going through lengthy textbooks or extensive notes.
- Effective Recap: One-page notes serve as an efficient tool for last-minute revision before exams, helping students refresh their memory and reinforce their understanding of critical topics.
- Easy to Carry: Students can easily carry these compact notes anywhere, making them convenient for on-the-go studying, whether at school, home, or during travel.
- Improved Focus: The condensed format encourages students to concentrate on the most essential points, reducing the risk of distraction from irrelevant information.
- Enhanced Retention: Summarized information is easier to remember, making it ideal for retaining key concepts and formulas for the exam.
- Organization: One-page notes often follow a structured format, aiding in the organization of information and making it easier for students to locate specific topics.
- Quick Reference: During the exam, one-page notes can be used as a quick reference guide to quickly recall important facts and concepts.
- Boosted Confidence: Having concise revision notes can boost students’ confidence in their exam preparedness, as they can easily review the entire syllabus in a short amount of time.
- Customization: Students can create their own one-page notes, allowing them to personalize the content to suit their learning style and preferences.
- Comprehensive Coverage: Despite their brevity, one-page notes should cover all essential topics and concepts, ensuring students don’t miss any important information.
In summary, one-page revision notes for CBSE Class 8 Science offer a convenient and effective way for students to review and consolidate their knowledge, ultimately aiding in better exam performance.
