The Human Eye and The Colorful world Class 10th Notes- Free NCERT Class 10 Science Chapter 11 Notes - Download PDF

The Human Eye and the Colourful World is a crucial chapter in Class 10 Science. Not only does it make you excel in your board exams, but it also provides a strong foundation for Class 11 and 12 Physics. This chapter describes how the human eye functions and discovers the wonderful world of light and colours surrounding us.

Chapter 10 of NCERT Class 10 Science Notes is prepared by experienced professionals. The Class 10 Science Chapter 10 notes are available for free, so all students can benefit from them. With easy explanations and simple diagrams, the notes help students understand difficult concepts such as refraction, dispersion, and rainbow formation. Learning from these notes will benefit you in board exams as well as in further studies of science!

Also, students can refer,

• NCERT Solutions for Class 10 Science Chapter 10 Human Eye and Colourful World
• NCERT Exemplar Class 10 Science chapter 11 Human Eye and Colourful World

Human Eye

• It is one of the most sensitive sense organs that is present in living organisms
• The image is formed on a screen that is light sensitive, known as the Retina.
• A thin membrane in the eye through which light enters the eye is known as the Cornea.
• Eyeballs are spherical.
• The presence of the lens helps in adjusting objects at different distances on the retina.
• The dark muscular structure which controls the size of the pupil is Iris. Hence, the pupil regulates the amount of light entering the eye.
• Real, inverted images are formed on the retina. It contains light-sensitive cells Rods and Cons. These cells send signals to the brain with the help of the optic nerve

Power of Accommodation

The focal lens of the lens in the eye can be decreased or increased. The eye lens gets thin when muscles are relaxed. This results in increased focal length. It helps to see distant objects. And when the eye lens becomes thick, the focal length is decreased and we see nearby objects.

Power of accommodation is the ability of the eye lens to adjust the focal length.

• The near Point of the Eye is at 25 cm and the Far Point of the Eye is infinity.

• In old age, the lens becomes milky and cloudy, this is called a Cataract. This leads to complete or partial loss of vision.

Defects of Vision and their Correction

The three common defects of vision are:

Myopia (Nearsightedness): In this, distant objects cannot be seen clearly, but nearby objects are visible.

Light from a far object forms an image before it reaches the retina.

Corrected using concave lens.

Hypermetropia (Far-sightedness): Nearby objects are seen clearly whereas distant objects can not be seen clearly.

Image of a nearby object is formed behind the retina.

Corrected using a convex lens.

Presbyopia: The power of accommodation decreases with ageing. They have difficulty in near vision as well as far vision. Bifocal lenses are used to correct the defects.

Dispersion of White Light in A Prism

When light falls on the prism, the prism splits the incident light into a band of seven colours. The colours observed are VIBGYOR (Violet, Indigo, Blue, Green, Yellow, Orange and Red). The band of colour is Spectrum. Thus, the splitting of incident light into different colours is Dispersion. The splitting is because of the bending of light rays at different angles. Violet light bends the most, whereas red light bends the least.

Recombination of spectrum of white light-

1 more prism is placed in an inverted position to get back the white light

The phenomenon of a rainbow is also because of the dispersion of light.

Atmospheric Refraction

Twinkling of Stars

When a star is lit in the atmosphere, it has to undergo refraction. The refractive index changes and the light bends towards the normal. As a result, the actual position of the star is a little bit different from its apparent position. We also know that the atmosphere of the earth is not stationary, so changes in the apparent position of the stars occur. Thus, we see them twinkling in the sky or the Earth’s atmosphere.

Advance Sunlight and Delayed Sunset

Due to the phenomenon of atmospheric refraction, the sun is visible 2 minutes before the actual sunrise, which is known as advanced sunlight. Just like the sunrise, the Sun is also visible 2 minutes after the actual sunset has taken place. This is known as Delayed Sunset.

Tyndall Effect

When a beam of light strikes tiny water droplets and suspended particles of dust the path of the beam becomes visible. This is the Tyndall Effect. Fine particles scatter, and particles of larger size scatter light of longer wavelengths.

Why does the sky appear blue?

The colour of the sky appears blue because of the scattering of light. When the sunlight passes through the atmosphere, the fine particles present in the air will scatter the blue colour since it has a shorter wavelength.

Why does the sky appear red during sunrise and sunset?

When the Sun rises and sets, its light which is present near the horizon passes through thicker layers of atmosphere and travels larger distances before reaching our eyesight. When the light of the Sun present overhead travels a comparatively shorter distance than light from the horizon, it results in the white appearance of the sun. Near the horizon, most of the blue light and shorter wavelengths are scattered by the particles. Therefore, the red light that reaches our eyes as it has the longest wavelength, hence the sky appears reddish.

Tips To Utilise CBSE Class 10 Science Chapter 10 Notes

1. Conceptual Understanding: Concentrate on comprehending the fundamental concepts, formulas, and theorems described in the Chapter 10 Science class 10 notes.
2. Practice: Solve problems from your notes on a regular basis to improve your problem-solving abilities and become acquainted with various question types.
3. Identify Weak Areas: Identify and improve your weak areas by going over those sections in your Science Class 10 Chapter 10 Notes pdf and practising more problems related to them.
4. Use Additional Resources: Supplement your learning with additional resources, such as reference books or online tutorials, to gain a better understanding of complex topics.
5. Regular Revision: Schedule regular revision sessions to strengthen your understanding of the chapter's concepts and improve your retention of the material.

Significance of NCERT Class 10 Science Chapter 10 Notes

Class 10 NCERT notes of The Human Eye and the Colourful World are excellent for last-minute revision and learning about the key points of the chapter. You can use these notes to go through all the major topics of the CBSE Class 10 Science syllabus and also for exams such as NEET in the future. You can even download these notes in PDF format so you can study them at any time, even offline.

The notes describe difficult things, such as refraction, dispersion, and vision defects in a very easy way. Learning becomes simple and enjoyable with the aid of diagrams and examples. These notes will assist you in getting better marks and making a good foundation for higher classes.

Class 10 Chapter Wise Notes

NCERT Solutions of Class 10 Subject Wise

• NCERT Solutions for Class 10 Maths
• NCERT Solutions for Class 10 Science

NCERT Class 10 Exemplar Solutions for Other Subjects:

• NCERT Exemplar Class 10 Maths solutions
• NCERT Exemplar Class 10 Science solutions