Ncert – class 10- science -Chapter 10 – The Human Eye and The Colourful World 1 Welcome to your Ncert - class 10- science -Chapter 10 – The Human Eye and The Colourful World 1 1. Which of the following phenomena cannot be explained by scattering of light? Tyndall effect Formation of rainbow White colour of clouds Blue colour of sky None 2. In Section A, defects of eye are given, in Section B, effects arising due to defects are given and in section C, remedies are given using lenses. Find the correct pair.Section ASection BSection C1. Myopia(x) Focal length increases(a) Bifocal lens2. Hypermetropia(y) Focal length decreases(b) Concave lens3. Presbyopia(z) Power of accommodation decreases(c) Convex lens (1 - y - b), (2 - x - c), (3 - z - a) (1 - y - a), (2 - x - a), (3 - z - c) (1 - z - b), (2 - z - b), (3 - y - b) (1 - x - a), (2 - y - c), (3 - x - a) None 3. Rising and setting sun appears to be reddish because: The sun is colder at sunrise or at sunset Scattering due to dust particles and air molecules is responsible for it Refraction is responsible for it Diffraction sends red rays to the earth at these times None 4. The process of re-emission of absorbed light in all directions with different intensities by the atom or molecule is called ____________. Dispersion of light Reflection of light Scattering of light Refraction of light None 5. A man suffering from myopia can read a book placed at 10 cm distance. For reading the book at a distance of 60 cm with relaxed vision, the focal length of the lens required will be: 30 cm −12 cm 45 cm −20 cm None 6. Match the column I with column II and select the correct option from the codes given below. Column IColumn II(a) Choroid(i) Detects light stimulus(b) Retina(ii) Absorbs light and prevents it from being reflected within the eyeball(c) Cornea(iii) Controls the size of the pupil(d) Iris(iv) Helps to focus light as it (a)-(i), (b)-(ii), (c)-(iii). (d)-(iv) (a)-(iii), (b)-(iv), (c)-(i), (d)-(iii) (a)-(ii). (b)-(i), (c)-(iv), (d)-(iii) (a)-(ii). (b)-(iii), (c)-(iv), (d)-(i) None 7. ________ lens is used to correct the defect of vision termed as presbyopia. Convex Bifocal Concave Contact None 8. The sky would appear red instead of blue if Atmospheric particles scatter all colours equally Atmospheric particles scatter red light more than the blue light The sun was much hotter Atmospheric particles scatter blue light more than red light None 9. Read the given statements and mark the correct option.Statement 1 : Abeam of white light gives a spectrum on passing through a hollow prism.Statement 2 : Speed of light outside the hollow prism is different from the speed of light inside the hollow prism. Both statements 1 and 2 are false. Statement 1 is true but statement 2 is false. Both statements 1 and 2 are true and statement 2 is the correct explanation of statement 1. Both statements 1 and 2 are true but statement 2 is not the correct explanation of statement 1. None 10. Long-sightedness or hypermetropia can be corrected by Bifocal lens Convex lens Concave lens Planar lens None 11. A person who can see the nearer objects clearly but not distant objects is suffering from .................... Blindness Emnetropia None of these Myopia None 12. Anil, an 8 th grade student, was asked to draw a figure explaining how the mammalian eye collects and focuses light, converting it into electrical signals. Which of the following flow charts correctly represents the process? Light → → Sclera → → Cornea → → Aqueous humor → → Pupil → → Lens → → Vitreous humor → → Retina → → Action potentials in neurons → → Optic nerve → → Brain. Light → → Sclera → → Vitreous humor → → Pupil → → Lens → → Aqueous humor → → Retina → → Action potentials in neurons → → Optic nerve Brain. Light → → Cornea → → Aqueous humor → → Iris → → Lens → → Vitreous humor → → Retina → → Action potentials in neurons → → Optic nerve → → Brain. Light → → Cornea → → Aqueous humor → → Pupil → → Lens → → Vitreous humor → → Retina → → Action potentials in neurons → → Optic nerve → → Brain. None 13. How is rainbow formed? A result of the dispersion of sunlight by the raindrops. A result of the reflection of sunlight by the raindrops. A result of the diffraction of sunlight by the raindrops. A result of the absorption of sunlight by the raindrops. None 14. A man can see the object between 15 cm and 30 cm. He uses the lens to see the far objects. Then due to the lens used, the near point will be at 30 cm 15 cm 100/3 cm 10/3 cm None 15. The near point of a person is 75cm. In order that he may be able to read book at a distance 25cm. The power of spectacles lenses should be −2D +3D +3.75D +2.6D None 16. A large-angle prism deviates a light ray does not deviate at all more equal to a small-angle prism less None 17. A person is suffering from 'presbyopia' ( myopia and hyper metropia both defects ) should use A bifocal lens whose upper portion is convex A concave lens A bifocal lens whose lower portion is convex A convex lens None 18. Which phenomenon does not play a role in the formation of rainbow ? Refraction Absorption Dispersion Reflection None 19. Sky looks bright from the earth on a sunny day but from any space station it is dark because no reflecting/scattering medium in space no natural source of light in space no luminous object in space eye deficiency None 20. A person can see clearly objects between 15 and 100 cm from his eye. The range of his vision if he wears close fittings spectacles having a power of 0.8 dipole is 17 to 500cm 17 to 250cm 12 to 250cm 5 to 500cm None 21. A person wears glasses of power −2.5 D. The defect of the eye and the far point of the person without the glasses are respectively Nearsightedness, 40 cm Farsightedness, 40 cm Astigmatism, 40 cm Nearsightedness, 250 cm None 22. Stars are not visible in the day time because Stars do not reflect sun rays during day Start vanish during the day Atmosphere scatters sunlight into a blanket of extreme brightness through which faint stars cannot be visible Stars hide behind the sun None 23. A man can see distinctly from a distance of 0.5m. If he wants to read a book placed at a distance of 25cm, then what kind of lens should he use? Convex lens with focal length of − 50cm Concave lens with focal length of 50cm Concave lens with focal length of −50cm Convex lens with focal length of 50cm None 24. A person is suffering from myopic defect. He is able to see clear objects placed at 15 cm. What type and of what focal length of lens he should use to see clearly the objects placed 60 cm away Convex lens of 20 cm focal length Convex lens of 12 cm focal length Concave lens of 20 cm focal length Concave lens of 12 cm focal length None 25. The near point of a hypermetropic person is 75 cm from the eye. What is the power of the lens required to enable the person to read clearly a book held at 25 cm from the eye? 0.75 D 1 D 2.67 D 1.5 D None 26. When white light passes through the achromatic combination of prisms, then what is observed Only dispersion Deviation and dispersion Only deviation None of the above None Time's up Please Share This Share this content Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Leave a Reply Cancel replyCommentEnter your name or username to commentEnter your email address to commentEnter your website URL (optional) Save my name, email, and website in this browser for the next time I comment.
