Light class 8 Notes Science

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Light class 8 Notes Science in PDF are available for free download in myCBSEguide mobile app. The best app for CBSE students now provides Light class 8 Notes Science latest chapter wise notes for quick preparation of CBSE exams and school-based annual examinations. Class 8 Science notes on chapter 16 Light Science are also available for download in CBSE Guide website.

Class 8 Science notes Chapter 16 Light

Download CBSE class 8th revision notes for chapter 16 Light in PDF format for free. Download revision notes for Light class 8 Notes and score high in exams. These are the Light class 8 Notes prepared by team of expert teachers. The revision notes help you revise the whole chapter 16 in minutes. Revision notes in exam days is one of the best tips recommended by teachers during exam days.

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CBSE Class 8 Revision Notes Science Light

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.

Light class 8 Notes Science

Light class 8 Notes Science. CBSE quick revision note for class-8 Science, Chemistry, Math’s, Biology and other subject are very helpful to revise the whole syllabus during exam days. The revision notes covers all important formulas and concepts given in the chapter. Even if you wish to have an overview of a chapter, quick revision notes are here to do if for you. These notes will certainly save your time during stressful exam days.

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