Class 10 Science - ODISHA
Human Eye and Colourful World
The chapter 'Human Eye and Colourful World' in Class 10 Science explores the fascinating structure and working of the human eye, alongside natural optical phenomena. Students learn about the power of accommodation, common vision defects like myopia and hypermetropia, and their corrections using lenses. Furthermore, it explains how light interacts with the atmosphere and prisms, causing phenomena such as the refraction of light, dispersion through a glass prism, total internal reflection, atmospheric refraction leading to twinkling of stars, and the scattering of light like the Tyndall effect and the blue colour of the sky. This chapter is vital for board exams as it tests both conceptual understanding and diagrammatic skills.
Start Learning FreeKey Concepts
Power of Accommodation
The ability of the ciliary muscles to adjust the focal length of the eye lens so that objects at various distances can be clearly focused on the retina.
Myopia (Short-sightedness)
A vision defect where a person can see nearby objects clearly, but distant objects appear blurred because the image forms in front of the retina. It is corrected using a concave lens.
Hypermetropia (Long-sightedness)
A vision defect where a person can see distant objects clearly, but nearby objects appear blurred because the image forms behind the retina. It is corrected using a convex lens.
Dispersion of Light
The splitting of white light into its seven constituent colours when it passes through a glass prism due to different speeds of different wavelengths of light.
Atmospheric Refraction
The refraction of light by the earth's atmosphere, which causes phenomena like the twinkling of stars, advanced sunrise, and delayed sunset.
Scattering of Light and Tyndall Effect
The phenomenon in which light is redirected in all directions when it interacts with colloidal particles, making the path of a light beam visible.
Important Formulas
Board Exam Info
In the Odisha BSE Class 10 Science board examination, this chapter typically carries around 5 to 7 marks. Questions frequently include ray diagrams for eye defects and their corrections, conceptual questions on atmospheric refraction (like twinkling of stars or blue sky), and numerical problems based on lens power.
Frequently Asked Questions
Why do the stars twinkle while planets do not?
Stars are distant point-sized sources of light. As starlight passes through the varying refractive indices of the earth's atmosphere, it bends differently at different moments, making them appear to twinkle. Planets are closer, acting as extended sources of light, so the variations average out to zero.
Why is the danger signal light red in colour?
Red light has the longest wavelength in the visible spectrum. Consequently, it is least scattered by fog, smoke, or air molecules, allowing it to travel the longest distance and remain visible from afar.
What is the far point and near point of a normal human eye?
The near point (least distance of distinct vision) for a normal human eye is 25 cm, while the far point is infinity.
Learn Human Eye and Colourful World with Your AI Tutor
10 different ways to study this chapter. Free for 3 chapters per day.
Lecture
Key Points
Interactive
Quiz
Flashcards