If you’re preparing for your Class 10 Science exam and looking for accurate, exam-ready questions and answers from the chapter The Human Eye and the Colourful World, you’re in the right place. This guide by Convex Classes Jaipur covers Human Eye Class 10 Questions and Answers—from NCERT intext and exercise questions to extra important questions often asked in board exams.
Chapter Overview: The Human Eye and the Colourful World
This chapter explains:
- Structure and functioning of the human eye
- Defects of vision and their correction
- Refraction through prism
- Dispersion and scattering of light
- Atmospheric phenomena like twinkling of stars and red sunrise/sunset
NCERT Exercise Questions (Page 197–198)
Q1. The human eye can focus objects at different distances by adjusting the focal length of the eye lens. This is due to: Ans:
(b) Accommodation
Q2. The human eye forms the image of an object at its: Ans:
(d) Retina
Q3. The least distance of distinct vision for a young adult with normal vision is about:
Ans: (c) 25 cm
Q4. The change in focal length of an eye lens is caused by the action of the:
Ans: (c) Ciliary muscles
Q5. A person needs a lens of power -5.5 D for distant vision and +1.5 D for near vision. What are the focal lengths?
Ans:
- Distant vision: f = -18.18 cm
- Near vision: f = +66.67 cm
Q6. The far point of a myopic person is 80 cm in front of the eye. What is the nature and power of the lens required to correct the problem?
Ans: Concave lens; Power = -1.25 D
Q7. Make a diagram to show how hypermetropia is corrected. The near point of a hypermetropic eye is 1 m. What is the power of the lens required to correct the defect?
Ans: Convex lens; Power = +3.0 D
Q8. Why is a normal eye not able to see clearly the objects placed closer than 25 cm?
Ans: Because the ciliary muscles cannot contract further to increase the curvature of the lens.
Q9. What happens to the image distance in the eye when we increase the distance of an object from the eye?
Ans: Image distance remains constant; the eye adjusts focal length to keep image on retina.
Q10. Why do stars twinkle?
Ans: Due to atmospheric refraction; light from stars bends unpredictably, causing brightness to vary.
Q11. Explain why the planets do not twinkle.
Ans: Planets are closer and appear as extended sources; fluctuations average out, so they don’t twinkle.
Q12. Why does the Sun appear reddish early in the morning?
Ans: Due to scattering of shorter wavelengths; only red light reaches the observer.
Q13. Why does the sky appear dark instead of blue to an astronaut?
Ans: No atmosphere in space means no scattering of sunlight—sky appears black.
NCERT Intext Questions with Answers
Q1. What is meant by power of accommodation of the eye?
Ans: It is the ability of the eye lens to adjust its focal length to focus on near and distant objects. This is done by the ciliary muscles.
Q2. A person with a myopic eye cannot see objects beyond 1.2 m distinctly. What should be the type of corrective lens used?
Ans: A concave lens of suitable focal length should be used to correct myopia.
NCERT Exercise Questions (Page 198)
Q1. The human eye forms the image of an object at its:
Ans: (d) Retina
Q2. The least distance of distinct vision for a young adult is:
Ans: (c) 25 cm
Q3. A person needs a lens of power -5.5 D for distant vision and +1.5 D for near vision.
What are the focal lengths? Ans:
- For distant vision: f = -18.18 cm
- For near vision: f = +66.67 cm
Extra Important Questions (Frequently Asked in Exams)
Q1. Why do stars twinkle but planets do not?
Ans: Stars are point sources of light and their light gets refracted through atmospheric layers, causing twinkling. Planets appear larger and their light doesn’t fluctuate as much.
Q2. Why does the sky appear blue?
Ans: Due to scattering of shorter wavelength (blue) light by air molecules.
Q3. What is the function of the iris in the human eye?
Ans: Iris controls the size of the pupil and regulates the amount of light entering the eye.
Q4. What is the cause of hypermetropia and how is it corrected?
Ans: Hypermetropia occurs when the eyeball is too short or the lens has too long a focal length. It is corrected using a convex lens.
Mind Map Summary
- Defects of Vision: Myopia, Hypermetropia, Presbyopia
- Correction: Concave lens (Myopia), Convex lens (Hypermetropia)
- Phenomena: Refraction, Dispersion, Scattering
- Applications: Rainbow formation, Twinkling of stars, Red sunrise/sunset
Why Convex Classes Jaipur?
We don’t just give answers—we decode concepts, provide grammar-rich explanations, and help you score higher with clarity and confidence. Bookmark this page and share it with friends who need Class 10 Human Eye Q&A in Hindi or English.
Class 10th Hindi Chapter 3 Question Answer
class 10 sanskrit chapter 11 hindi translation
class 10 sanskrit chapter 10 hindi translation
