LooLooking for reliable SEBA Class 10 Science Chapter 11 (The Human Eye and the Colourful World) extra questions and answers for the 2026–27 academic year? Access important short questions, conceptual explanations on vision defects, ray diagrams for lens corrections, atmospheric refraction phenomena, and previous year HSLC practice notes to score top marks.
EXTRA QUESTION AND ANSWER
Q1. What is the function of the cornea in the human eye?
Answer: The function of the cornea in the human eye is to act as the transparent front layer that refracts (bends) most of the incoming light and helps focus it onto the retina.
Q2. What are the roles of the iris and pupil in regulating light?
Answer: The roles of the iris and pupil in regulating light is that the iris controls the size of the pupil, while the pupil expands in dim light and contracts in bright light to regulate the amount of light entering the eye.
Q3. What is the retina and what is its function?
Answer: The retina is a light-sensitive screen at the back of the eye where images are formed. It converts light into electrical signals and sends them to the brain through the optic nerve.
Q4. Explain briefly how we see objects around us.
Answer: Light reflected from an object enters the eye, gets focused by the cornea and lens onto the retina, and the brain interprets the electrical signals to produce vision.
Q5. What is the main function of the eye lens?
Answer:The main function of the eye lens is to adjust its shape and focal length to focus light rays coming from different distances accurately onto the retina.
SEBA Class 10 Science Chapter 11 Notes
Q6. What is meant by the least distance of distinct vision?
Answer: It is the minimum distance at which an object can be seen clearly without any strain on the eye. For a normal human eye, it is about 25 cm.
Q7. What is the far point of a normal human eye?
Answer: The far point is the farthest distance up to which a normal eye can see objects clearly, which is infinity.
Q8. Define the power of accommodation of the eye.
Answer: The ability of the eye lens to adjust its focal length to focus both nearby and distant objects clearly on the retina is called power of accommodation.
Q9. Why do our eyes feel strained when we read a book too close to them?
Answer: Reading too close forces the ciliary muscles to contract continuously to make the lens thicker, which causes strain on the eye muscles.
Q10. What is a cataract and how can it be corrected?
Answer: A cataract is a condition where the eye lens becomes cloudy, leading to blurred or lost vision. It is corrected by surgery to replace the cloudy lens with an artificial lens.
Q11. What is myopia (near-sightedness) and how is it corrected?
Answer: Myopia is a vision defect in which a person can see nearby objects clearly but cannot see distant objects distinctly. It is corrected using a concave lens of suitable power.
The Human Eye and Colourful World Class 10 SEBA Extra Question Answer
Q12. What are the two main causes of myopia?
Answer: The two causes of myopia are:
- Excessive curvature of the eye lens.
- Elongation of the eyeball.
Q13. What is hypermetropia (far-sightedness) and how is it corrected?
Answer: Hypermetropia is a vision defect in which a person can see distant objects clearly but cannot see nearby objects distinctly. It is corrected using a convex lens of suitable power.
Q14. What are the main causes of hypermetropia?
Answer: The main causes of hypermetropia are:
- Focal length of the eye lens is too long.
- Eyeball has become too small.
Q15. What is presbyopia and how is it corrected?
Answer: Presbyopia is an age-related vision defect in which the eye loses its power of accommodation, making it difficult to see nearby objects clearly. It is corrected using bifocal lenses.
HSLC Science Chapter 11 Important Short Questions
Q16. Why do some elderly people need bifocal lenses?
Answer: Elderly people use bifocal lenses because they suffer from both myopia and hypermetropia. The upper part contains a concave lens for distant vision and the lower part contains a convex lens for reading.
Q17. What are two advantages of having two eyes instead of one?
Answer: Two advantages are:
- It provides a wider field of view (about 180°).
- It gives three-dimensional (3D) vision and accurate depth perception.
Q18. What is a glass prism?
Answer: A glass prism is a transparent optical element with two triangular bases and three rectangular lateral surfaces that bends and refracts light.
Q19. Define the angle of deviation in a prism.
Answer: The angle formed between the direction of the incident ray and the emergent ray after passing through a prism is called the angle of deviation.
Q20. What is dispersion of light?
Answer: The splitting of white light into its seven constituent colors when it passes through a transparent medium like a glass prism is called dispersion of light.
Class 10 Science Chapter 11 Important Questions SEBA 2026-27
Q21. Name the seven colors of the visible spectrum in order.
Answer: The seven colors are Violet, Indigo, Blue, Green, Yellow, Orange, and Red (VIBGYOR).
Q22. Why does white light split into different colors when it passes through a glass prism?
Answer: Different colors of light travel at different speeds in glass and bend (refract) through different angles. Violet light bends the most, while red light bends the least.
Q23. Describe Isaac Newton’s recombination experiment with two prisms.
Answer: Newton passed white light through a glass prism to split it into seven colors. When he placed an identical inverted prism in its path, the seven colors recombined to form white light again.
Q24. What conclusion did Isaac Newton draw from his prism experiment?
Answer: Newton concluded that white light is made up of a mixture of seven different colors.
Q25. What is atmospheric refraction?
Answer: Atmospheric refraction is the bending of light as it passes through different layers of Earth’s atmosphere that have varying densities and temperatures.
Q26. Why do stars appear to twinkle at night?
Answer: Starlight passes through changing layers of the atmosphere with varying densities. This continuously bends the light rays, making the star appear brighter and dimmer randomly, which causes twinkling.
Q27. Why do planets not twinkle like stars?
Answer: Planets do not twinkle because they are much closer to Earth and appear as extended sources of light made of many point sources. The light coming from all these points averages out, neutralizing the twinkling effect.
Q28. Explain why advanced sunrise and delayed sunset occur.
Answer: Due to atmospheric refraction, sunlight bends as it enters the atmosphere, allowing us to see the Sun about 2 minutes before it actually rises above the horizon and 2 minutes after it sets.
Q29. Why does the Sun’s disc appear flattened at sunrise and sunset?
Answer: The atmospheric refraction of light from the top and bottom edges of the Sun’s disc happens by different amounts, making the Sun appear flattened.
Q30. Why does the sky appear blue during the day, but the Sun appears red at sunrise and sunset?
Answer: Air molecules scatter shorter wavelengths (blue light) more effectively, making the clear sky look blue. At sunrise and sunset, sunlight travels a longer distance through the atmosphere, so blue light is scattered away, leaving mostly longer wavelengths (red light) to reach our eyes.
SEBA Class 10 Science Chapter 11 Extra Questions
🔬 Updated Extra Questions Guide Notice: This page features an extensive collection of SEBA Class 10 Science Chapter 11 (The Human Eye and the Colourful World) Extra Questions and Detailed Answers updated for the 2026–27 academic session. All optical diagrams, defect correction steps, and atmospheric light phenomena strictly follow the latest revised Assam Board (SEBA) curriculum.
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