Explain with an example. The Human Eye: It is a natural optical instrument which is used to see the objects by human beings. Draw a ray diagram showing the dispersion through a prism when a narrow beam of white light is incident on one of its refracting surfaces. Therefore, the sky appears blue from the surface of the Earth. The far point of a normal human eye is at infinity. → Violet is the most deviated colour as it has smallest wavelength in visible spectrum. Save my name, email, and website in this browser for the next time I comment. Answer: Name the component of white light that deviates the least and the component that deviates the most while passing through a glass prism. The person with … What do you understand by spectrum of white light? → Diameter of eye ball – 2.3 cm. Question 3. It provides most of the refraction of light. A person is advised to wear spectacles with convex lenses. Answer: (iii) Pupil Spreading of light in various directions by colloid particles. (b) A glass prism is able to produce a spectrum when white light passes through it but a glass slab does not produce any spectrum. Solution : Convex lens. How does this happen? Write the name of this defect. (a) Myopia is the defect of the eye vision due to which a person can see the nearly objects clearly but cannot see the far objects so distinctly. Human Eye and Colourful World Extra Questions Very Short Answer Type. It is least scattered by fog and smoke and can be seen in the same colour over a long distance. Answer: As a result the sun appears higher than its actual position. (2012 OD) Answer: The focal length of eye-lens can be changed by changing its shape by the action of ciliary muscles. This spectrum undegoes internal reflection (inside the raindrop) and finally refracted again when it comes out of the raindrop. → The amount of light coming from stars also vary due to changing Refractive Index of atmosphere. Question 1. → Both these effects are responsible for twinkling of stars. … Zigya App (a) What is hypermetropia? → The upper layer of atmosphere contains very fine particles of water vapours and gases. (iii) Even larger particles scatter all the colours of light that is why it appears white. Answer: → The angle of incidence should exceed critical angle, the light reflects in the denser medium. The refractive index of hot air is less than that of cool air. A person can see clearly only up to 3 metres. Question 1: What kind of lens is present in the human eye ? → Light should enter obliquely from a denser to a rarer medium. Question 6. ... CBSE Previous Year Question Papers Class 10 Science; CBSE Previous Year Question Papers Class 12 Physics; CBSE Previous … What is Tyndall effect? accommodation. However, there is lateral displacement. The defect of the vision is hypermetropia. All NCERT textbook questions have been solved by our expert teachers. The Human Eye and Ray Optics - Human Eye and Colourful World, Class 10, Science. The human eye can focus objects at different distances by adjusting the focal length of the eye lens. Answer: Question 2. Parts of Human Eye • Cornea: It is the outermost, transparent part. 2. Causes of myopia: Myopia is caused: Myopia can be corrected by using a concave lens of suitable focal length in the spectacles of such a person. Using the phenomenon of scattering of light, explain why there is a difference in the colour of the sun as it appears during sunrise and at noon. Question 25. The difference of time is about 2 minutes each for early rise and late setting of the Sun. Students who are in Class 10 or preparing for any exam which is based on Class 10 Science can refer NCERT Book for their preparation. The maximum accommodation of a normal eye is reached when the object is at a distance of 25 cm from the eyes. What is meant by scattering of light? In the following diagram, the path of a ray of light passing through a glass prism is shown below. CBSE Class-10 Revision Notes and Key Points. How is presbyopia corrected? For most people, the near point gradually recedes and the far point comes closer. This is called internal reflection. Extra Questions for Class 10 Science Chapter 11 Human Eye and Colourful World with Answers Solutions. The sun can be seen about two minutes before actual sunrise because of atmospheric refraction. How does refraction of light take place in the atmosphere? For an astronaut, the sky would appear dark because in space there is no atmosphere to scatter light. Human Eye Diagram class 10 | How to Draw Human Eye Diagram … During sunset and sunrise, the sun is near horizon and therefore the sunlight has to travel larger distance in atmosphere. Answer: The human eye is the natural convex lens that refracts light. → A myopic person can see nearby objects clearly but cannot see distant objects clearly. What should the appearance of the sky be during the day for an astronaut staying in the international space station orbiting the Earth? Answer: Write two causes for development of this defect. → Then it reflects internally and again refracts as it come out of the drop and the seven colours reach the eye of observer in form of rainbow. (i) Concave mirror After the dispersion of light and internal reflections, the band of colours reaches observer’s eye in the form of a rainbow. The defect of vision is myopia. Question 9. Seven colours of spectrum are violet, indigo, blue, green, yellow, orange and red also known as ‘VIBGYOR’. Ability of the eye lens to focus nearby as well as distant objects on the retina by changing the curvature or focal length of the eye lens is known as power of accommodation. What is meant by dispersion of white light? A person cannot see distinctly objects kept beyond … It is also called eyesight. Answer: So he can see the objects clearly only in one plane. Download free CBSE Sample paper for Class 10, Physics. Answer: → When white light is passed through a glass prism, it splits into its seven constituent colours to form a band of seven colours. A Glimpse of CBSE Class 10 Science Marking Scheme • Three phenomenon which are involved in rainbow formation are : → Some water droplets remain suspended in air after rain. → Due to changing Refractive Index (RI) of medium, the light appears to come from different directions. Question 5. Danger signal lights are red in colour because the red coloured light having longer wavelength is scattered the least by fog or smoke. Due to this, the slightly different images of the successive pictures present on the film merge smoothly with one another and give us the feeling of continuity and moving images. Different wavelengths deviate differently in the prism because the angle of refraction for different colours having different wavelengths is different while passing through the glass prism. Answer: Question 4. (ii) Near point or 25 cm. (a) Myopia It arises due to the gradual weakening of the ciliary muscles and diminishing flexibility of the eye lens. NCERT Book for Class 10 Science Chapter 11 Human Eye and Colourful World is available for reading or download on this page. All the seven colours combined by the inverted prism and emerged as white light. When sunlight passes through the atmosphere, the fine particles in air scatter the blue colour more strongly than red. due to decrease in the focal length of the eye lens. Thus, scattering of light makes the particles visible. Class 10 Class 12. Draw a simple diagram of the human eye and label clearly the cornea, iris, pupil, ciliary muscles, eye-lens, retina, optic nerve and blind spot. The human eye(s) are located in the specialized sockets carved out in the human skull. → When light enters the rain drop, it first refracts and disperses. Question 10. Water vapours condense to form water droplets due to larger size of droplets, all colours of light are scattered and clouds appear white. Answer: (b)Why is the normal eye unable to focus on an object placed within 10 cm from the eye? This is possible only when you have the best CBSE Class 10 Science study material and a smart preparation plan. Hypermetropia (Long-sightedness): A person can see distant objects distinctly but cannot see nearby objects so clearly in this case, the image is formed behind the retina. A person needs a lens of power -4.5 D for correction of her vision. NCERT Solutions for Class 10 explains the detailed structure of the human eye. → Stars are very far from us, so they behave as point source of light. The revision notes covers all important formulas and concepts given in the chapter. This defect can be corrected by using cylindrical lenses of suitable focal length and suitable axis in the spectacles. As rays of all colours emerge in the same direction, i.e., the direction of the incidence of white light, there is no dispersion. Function of Ear. This phenomenon is called dispersion. (i) Mirrors used by dentists to examine teeth. Following are the important function of the ear: Hearing. Question 7. 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Or → So, the light coming from a star near the horizon has to travel from rarer to denser medium and it bends towards the normal. He would find that for all angles of incidence the ray of light bends: ... We hope the given NCERT MCQ Questions for Class 10 Science Chapter 11 Human Eye and Colourful World with Answers Pdf free download will help you. → Focal length of the eye lens becomes too long. In fact the sensation produced by the image of an object lasts for nearly 1/16th of a second on retina. → So rays bend towards the normal. (i) Path of light becomes visible when light enters a dark and dusty room through a slit or ventilator. Answer: (i) the eye defect myopia The water droplets act like small prisms. Name the various colours of spectrum of white light in proper sequence. Thus, the normal eye is unable to focus an object placed within 10 cm from the eye because it is beyond its power of accommodation. Extra Questions for Class 10 Science Chapter 11 Human Eye and Colourful World with Answers Solutions. The light of longer wavelength (red colour) will reach our eye. Dispersion of White Light by Glass Prism. (a) What is dispersion of white light? Question 3. Our eye is the most important natural optical instrument. Question 1. What is colour blindness? Also indicate the order of the … → Clouds are formed by water vapours. The power of accommodation of the eye decreases with ageing. Question 7. In which of the two cases is the focal length of the eye-lens more? State the changes that occur in the curvature and focal length of the eye lens while viewing (a) a distance object, (b) nearby objects. What eye defect is hypermetropia? Science NCERT Grade 10, Chapter 11, Human Eye and Colourful World lays emphasis on the understanding of the working of the human eye along with the functions of different parts of the human eye. What are the essential parts of the eye and their functions → The refractive index of earth’s atmosphere in general increases from top to bottom. stars appears to come from different directions. (CBSE 2009) Answer: (a) Hypermetropia: It is also called long-sightedness. As these slow down by different amounts, different colours are refracted through different angles which causes dispersion. Why there is no dispersion of light refracted through a rectangular glass slab? Use this phenomenon to explain why the clear sky appears blue or the sun appears reddish at sunrise. With the help of labelled ray diagrams show (a) The splitting up of white light into its constituent colours on passing through a refracting medium like a glass prism is called dispersion of light. Structure of Eye. Human Eye and Colourful world Class 10 Important Questions with Answers Science Chapter 11 Human Eye and Colourful world Class 10 Important Questions Short Answer Type. NCERT Exemplar Class 10 Science Unit 11 Human Eye and Colourful World. As the object approaches from infinity towards the eye, the focal length of the eye lens decreases (or vice-versa) so as to maintain the same image distance. Such a person may suffer from myopia and hypermetropia. Hence sun appears red. A person cannot see objects beyond 80 cm from his eye while a person with normal eyesight can see object easily placed upto 160 cm from the eye. Class 1 - 3; Class 4 - 5; Class 6 - 10; Class 11 - 12; CBSE. → It is the defect of vision due to which an old person cannot see the nearby objects clearly due to loss of power of accomodation of the eye. Answer: Each human eye sizes for approximately 2.5 cm in diameter. In bifocal lens, upper portion is of concave or diverging lens to view far off objects and lower part is of convex or converging lens to view nearby objects. Question 13. It has "nearly a spherical shape. Question and Answer forum for K12 Students. State the two causes of myopia. The pictures in the form of a long film are projected on the screen at a rate of about 24 pictures per second. The near point of a normal human eye is at a distance of 25 centimetres from the eye. → The air above hot surface becomes hot and rises. Given: = -25 cm. A man with spectacles can read a book placed at 25 cm. Answer: Dispersion of light concept is made understandable in a simple way. (b) What is the focal length of the corrective lens? The first prism splits the white light into its seven colour components. What causes presbyopia? How can you along with your classmates contribute in this noble cause? without putting any strain on the eye. The main parts of a human eye are: Sclera NCERT Exemplar for Class 10 Science Chapter 11 The Human Eye and The Colourful World Multiple Choice Questions 1. Draw a ray diagram to show the path of a narrow beam of white light, through a combination of two identical prisms arranged together in inverted position with respect to each other, when it is allowed to fall obliquely on one of the faces of the first prism of the combination. All colours of light travel at the same speed in a vacuum. In this page, you can find CBSE Class 10 Science Chapter 11 Extra Questions and Answers Human Eye and Colourful World Pdf free download, NCERT Extra Questions for Class 10 Science will make your practice complete. Which defect of the eye can be corrected by using a cylindrical lens? Answer: To the observer O these rays appear to come from B which is above horizon. Question 1. (i) If particles are very fine, they scatter mainly the blue colour of light (shorter wavelength). CBSE Class 10 Science Notes Chapter 11 Human Eye and Colourful World. Solution: → Wavelength of red light is about 1.8 times to that of blue light. It is for this reason that the sun is visible to us a little before it rises above the horizon and so also till a little later it sets below the horizon. This increases the curvature of the eye lens. Explain, why a normal eye is not able to see distinctly the objects placed closer than 25 cm. However, the focal length of the eye lens cannot be decreased below a certain limit. (a) What is myopia? → Due to this most of the blue light (shorter wavelength) are scattered away by the particles. NCERT Solutions for Class 10 Science Chapter 11: The Human Eye and Colourful World. Why do different rays deviate differently in the prism? The + sign with for the power indicates a convergent lens. Question 22. For scattering of light, particles are required. The phenomenon in which a part of the light incident on a particle is redirected in different directions is called the scattering of light. Question 10. Since we see the blue light from everywhere overhead, the sky appears blue. If you have any queries regarding Human Eye and Colourful World … → Since the physical conditions of the earth’s atmosphere are not constant the light from. All the NCERT exemplar solutions are framed in a systematic manner according to the latest CBSE class 10 science syllabus (2020-21). BNAT; Classes. lamge distance in the eye is the distance between the eye lens and the retina and it is fixed. (ii) correction of myopia using a lens. → The sky would appear dark to an astronaut in the space as scattering is not very prominent at such high altitude due to absence of particles. Solution: → This results in fluctuation of apparent position of star. Class 10 Science The Human Eye and the Colourful World – Get here the Notes for Class 10 Science The Human Eye and the Colourful World. The human eye structure and function makes it easy to distinguish the objects based on colour, size and other parameters. (ii) correction of hypermetropia by using a lens. This enables us to see distant objects clearly. This reduces the vision in old age. (b) 1. The tiny dust particles present in the air of room scatter the beam of light all around the room. → Affected person can see far objects clearly but cannot see nearby objects clearly. The scattered blue light enters our eyes. State the objectives of organising such campaigns in schools. A person cannot see objects nearer than 75 cm from his eyes while a person with normal vision can see objects upto 25 cm from his eyes. (a) What kind of defect in vision is she suffering from? A student is observing the diagram showing the path of a ray of light passing through a glass prism. By using two identical prism, one placed inverted with respect to the other we get a narrow beam of white lgiht incident on one prism emerges out of the second prism as white light. Least deviated component: Red This defect of the eye is hypermetropia. As a result, the cornea has different curvatures in different directions of the horizontal and vertical planes. (ii) Stars near the horizon appear slightly higher than their actual position. Question 3. Answer: (ii) The smallest distance, at which the eye can see objects clearly without strain. What is meant by ‘persistence of vision’? The focal length of the eye lens decreases. Answer: Question 11. How did Newton, using two identical glass prisms, show that white light is made of seven colours? When a beam of light enters a smoke-filled dark room through a small hole, then its path becomes visible to us. Students can solve NCERT Class 10 Science Human Eye and Colourful World Multiple Choice Questions with Answers to know their preparation level. → Red is the least deviated colour as it has largest/longest wavelength. In the bright sunlight, iris causes the pupil to become smaller so that only a small portion of light enters the eye and rods of the retina are also adjusted in the same way. Most deviated component: Violet. Colour blindness is that defect of the eye due to which a person is unable to distinguish certain colours, sometimes even the primary colours. The ability of the human eye to continue to see the image of an object for very short duration even after the removal of that object is called persistence of vision. Given, that u = – 25 cm and y = –75 cm. → It results in fluctuation in apparent position of object. It is produced by dispersion of sunlight by tiny water droplets, present in the atmosphere. Draw a labelled diagram to explain. CBSE Previous Year Question Paper for Class 10, CBSE Previous Year Question Paper for Class 12. In this article you will get CBSE Class 10 Science chapter 11, Human Eye and Colourful World: NCERT Exemplar Problems and Solutions (Part-II). A person is advised to wear spectacles with concave lenses. Refraction of Light through a Rectangular Glass Slab. → It enhances the ability to detect faint objects. Answer: Prescribe a lens for spectacles so that he can see clearly up to 12 metres. Defects of Vision in Eye (Myopia) Defects of Vision in Eye (Hypermetropia) Refraction of Light through a Glass Prism. Answer: Question 4. However, at noon sunlight would travel relatively shorter distance only a little blue and violet colours are reflected and it is nearly the white light which reaches our eye. Astigmatism. This is due to. → Such people require bifocal lens for correction. At sunrise and sunset when the sun is below the horizon, the light rays starting from sun are incident on these layers. (b) Curvature increrases. Studyrankers is a free educational platform for cbse k-12 students. (ii) Iris What is the cause of dispersion? Atmospheric Refraction Effects. (i) Apparent flickering of objects placed behind a hot object or fire. Answer: Question 18. Here, v= -3 m, u = -12 m, f = ? Solution: This defect is then corrected by using bi-focal lenses of suitable focal lengths. The layers of air nearer to earth are denser than those above it. The least distance of distinct vision for a normal eye is (a) infinity (b) 25 cm (c) 2.5 cm (d) 25 m. Answer. State reason to justify your answer. The planets are much closer to the earth and are thus seen as extended sources. Image Formation by Concave Mirror. The type of questions that will be asked from NCERT Class 10 Science Unit 11 are displayed in the below provided NCERT Exemplar Class 10 Science Unit 11. Their functions Question 10 thus seen as extended sources ‘ VIBGYOR ’ dispersion of light concept is made of colours. Orange and red also known as the least while the Violet the most while passing a... Red is the focal length 4 m should be used Extra Questions very Short answer type the! 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Or download on this page free sample papers, Notes, important.... The next time i comment are scattered away by the molecules of the eye decreases with.... Different directions of the object, as seen through the atmosphere 6 - 10 ; Class 4 - ;... With your classmates contribute in this noble cause or raindrop ) it refraction! Ray of light coming from stars also vary due to the scattering of sunlight by tiny water droplets, slow. ) near point or 25 cm using concave lens scattering light of shorter wavelength ) are located in the?... Same speed in a cinema hall a free educational platform for CBSE k-12 students appear red dispersion. Science human eye: working of a diagram with its structural representation covering the parts... Observing the diagram showing the path of light travel at the blue colour of human. Sky raindrop after a rain used in the eye lens are located in the spectacles the old having.: Violet 4 - 5 ; Class 4 - 5 ; Class 11 - 12 ; CBSE is... 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