The band of seven colours formed on white screen when a beam of white light (or sunlight) is passed through a glass prism is called spectrum of white light. Answer: What is astigmatism? The sun can be seen about two minutes before actual sunrise. Question 4. What is colour blindness? (CBSE 2009) Answer: (a) Hypermetropia: It is also called long-sightedness. The twinkling of a star is due to atmospheric refraction of starlight. Given, that u = – 25 cm and y = –75 cm. Answer: Human Eye and Colourful World - Know the working of a human eye, the difference between Cornea and Retina. Power of Accommodation: The ability of an eye to focus the distant objects as well as the near by objects on the retina by changing the focal length is called power of accommodation. These droplets behave as glass prism. → The amount of light coming from stars also vary due to changing Refractive Index of atmosphere. Question 1. What is Tyndall effect? Answer: 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. Question 7. This enables us to see nearby objects clearly. Studyrankers is a free educational platform for cbse k-12 students. … (i) Mirrors used by dentists to examine teeth. So, it is important to know the defects of vision and which type of lens can cure which defect. Answer: (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. What eye defect is hypermetropia? Explain the structure and function of such a lens. The far point of a normal human eye is at infinity. → Clouds are formed by water vapours. Why does the sky appear dark to astronauts? A collection of questions on CBSE- Human Eye and the Colourful World with solutions created by best teachers are available as a PDF … 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. → A myopic person can see nearby objects clearly but cannot see distant objects clearly. Extra Questions for Class 10 Science Chapter 11 Human Eye and Colourful World with Answers Solutions. Find the nature, the focal length and the power of the correcting lens used for the defective vision. State the changes that occur in the curvature and focal length of the eye lens while viewing (a) a distance object, (b) nearby objects. → Located in eye sockets in skull. Question 1. CBSE Class 10 Science Notes Chapter 11 Human Eye and Colourful World. Structure of Eye. Answer: A rainbow is a natural spectrum appearing in the sky … Answer: Your school has organised a campaign in the school and its neighbourhood in order to creat awareness about this fact and motivate people to donate their eyes after death. Why do different rays deviate differently in the prism? In this article you will get CBSE Class 10 Science chapter 11, Human Eye and Colourful World: NCERT Exemplar Problems and Solutions (Part-II). (i) If particles are very fine, they scatter mainly the blue colour of light (shorter wavelength). The Human Eye and Its Structure ‘Human Eye’ is the organ of vision of the human body that enables us to see. Question 12. 1. The defect of vision is myopia. The defect of the eye due to which a person is unable to distinguish between certain colours, is known as colour blindness. → Such people require bifocal lens for correction. (b) The ability of the eye lens to adjust its focal length is called automatic accommodation. The human eye is the natural convex lens that refracts light. It provides most of the refraction of light. At sunrise, light from the sun near the horizon passes through thicker layers of air and larger distance in the earth’s atmosphere before reaching our eye. Answer: A collection of questions on CBSE- Human Eye and the Colourful World with solutions created by best teachers are available as a PDF download. Far-sightedness/Long-sightedness/Hypermetropia. How is presbyopia corrected? Also indicate the order of the … 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. This is called internal reflection. Question 10. Question 23. (ii) Medium sized particles scatter mainly the red colour (longer wavelength). Question 8. Image Formation by Concave Mirror. The red light bends the least while the violet the most as shown below. (ii) correction of hypermetropia by using a lens. → The near-point of the old person having presbyopia gradually recedes and becomes much more than 25 cm away. Question 5. The water droplets act like small prisms. Question 24. (i) Path of light becomes visible when light enters a dark and dusty room through a slit or ventilator. Spreading of light in various directions by colloid particles. The pictures in the form of a long film are projected on the screen at a rate of about 24 pictures per second. The first prism splits the white light into its seven colour components. (iii) Advanced sunrise and delayed sunset. (ii) correction of myopia using a lens. accommodation. Question 6. ... For more information on the human ear, the structure of ear class 9, human ear parts, the function of the ear, and other related topics keep … lamge distance in the eye is the distance between the eye lens and the retina and it is fixed. Causes of hypermetropia: This defect arises because either: Hypermetropia can be corrected by using convex lens of suitable focal length in spectacles. NCERT Solutions for Class 10 explains the detailed structure of the human eye. → While sunset and sunrise, the colour of the sun and its surrounding appear red. As rays of all colours emerge in the same direction, i.e., the direction of the incidence of white light, there is no dispersion. State the two causes of myopia. The ciliary muscles of a normal eye are in their Question 11. This defect of the eye is hypermetropia. All the seven colours combined by the inverted prism and emerged as white light. → Sometimes a person may suffer from both myopia and hypermetropia. Get class 10 study materials at BYJU'S. Or Lakhmir Singh Physics Class 10 Solutions The Human Eyes And The Colorful World. You can also get free sample papers, Notes, Important Questions. Dispersion of light concept is made understandable in a simple way. It is due to persistence of vision that we are able to see movie pictures in a cinema hall. Near point or Least distance of distinct vision, Advantage of the eyes in front of the face. 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. Under these conditions, the image of one picture persists on the retina of the eye till the image of the next picture falls on the screen, and so on. Thus, scattering of light makes the particles visible. CBSE quick revision note for Class-10 Science, Chemistry, Maths, Biology and other subject are very helpful to revise the whole syllabus during exam days. Answer: During this, most of the shorter wavelengths present in it are scattered away from our line of sight by the molecules of air and other fine particles in the atmosphere. Answer: → This results in fluctuation of apparent position of star. Answer: The least distance of distinct vision for a normal eye is (a) infinity (b) 25 cm (c) 2.5 cm (d) 25 m. Answer. → Wavelength of red light is about 1.8 times to that of blue light. Answer: b. However, there is lateral displacement. → When white light is passed through a glass prism, it splits into its seven constituent colours to form a band of seven colours. → Due to changing Refractive Index (RI) of medium, the light appears to come from different directions. Explains the various defects that happen for human and also describes the ways to correct it. → When light enters obliquely from a denser medium to a rarer medium and the angle of incidence exceeds critical angle, the light reflects in the denser medium. Answer: (a) Myopia The Human Eye and Ray Optics - Human Eye and Colourful World, Class 10, Science. Why there is no dispersion of light refracted through a rectangular glass slab? The -ve sign with f indicates the concave lens. Question and Answer forum for K12 Students. Class 10 Class 12. Question 21. Answer: After refraction at two parallel faces of a glass slab, a ray of light emerges in a direction parallel to the direction of incidence of white light. Write about power of accommodation of human eye. (i) Apparent flickering of objects placed behind a hot object or fire. Since there are no particle in space, the sky appear dark to astronauts. Extra Questions for Class 10 Science Chapter 11 Human Eye and Colourful World with Answers Solutions. Cataract can be cured by eye surgery. How does atmospheric refraction affect sunrise and sunset? Question 11. (iii) Pupil → When the sun is below horizon, the rays have to pass from rarer to denser medium. → Diameter of eye ball – 2.3 cm. The Human Eye: It is a natural optical instrument which is used to see the objects by human beings. Answer: A person can see clearly only up to 3 metres. The light of longer wavelength (red colour) will reach our eye. The human eye structure and function makes it easy to distinguish the objects based on colour, size and other parameters. 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. What kind of retinal cells are lacking in person suffering from this defect? Retina: To act as a screen to obtain the image of object and generate electrical signals which are sent to the brain via optic nerves. Answer: (a) Lens becomes thin Answer: → Issac Newton was the first person who proved that sunlight is made up of seven colours : (i) He passed sunlight through a glass prism to form a band of seven colours. It arises due to the gradual weakening of the ciliary muscles and diminishing flexibility of the eye lens. (a) What is myopia? What do you mean by power of accommodation of an eye? Question 4. The difference of time is about 2 minutes each for early rise and late setting of the Sun. Function of Ear. Least deviated component: Red The eye resembles a - camera in many ways. Answer: The splitting of white light into its component colours is called dispersion of light. Zigya App (a) What is hypermetropia? Answer: This phenomenon is called dispersion. Formation of Rainbow. 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. 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. Answer: Explain with an example. Astigmatism. What is meant by scattering of light? Write the name of this defect. This is because focal length of the lens of a normal human eye cannot be decreased below certain limit i.e., 25 cm. 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. Explain the reason why stars appear to twinkle and the planets do not twinkle. So, light reaching us directly from the rising or setting Sun consists mainly of the longer wavelength red colour because of which the Sun appears red. To the observer O these rays appear to come from B which is above horizon. 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. What is meant by advance sunrise and delayed sunset. No, it will not show dispersion. How did Newton, using two identical glass prisms, show that white light is made of seven colours? Solution: With the help of ciliary muscles the human eye can change its curvature and thus alter the focal length of its lens. In the following diagram, the path of a ray of light passing through a glass prism is shown below. → Due to this most of the blue light (shorter wavelength) are scattered away by the particles. 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