Answer: It once again suffers refraction at M and emerges out along MN. Answer: Answer: The angle between two lateral faces of a prism is called the angle of the prism. Geometric optics is an optical model that describes the propagation of light in terms of rays. Let an incident ray PQ be incident obliquely from the air at point Q on the surface of the prism AB. Which colour will travel fastest in air? What are the seven colours obtained when light passes through prism? The air higher up in the sky is rarer and near the earth’s surface is denser. Explanation: White light is made up of seven colours (VIBGYOR). (d) angle of incidence. Question 2: A ray of light that enters the prism from a rarer medium, while entering the prism, at the point of incidence it will The factors on which the angle of deviation through a prism depends are: Question 3: In geometric optics, the rays of light are important to approximately determine the paths along which light propagates under certain conditions. The factors responsible for the refraction of light when passing through a prism are: The angle between two lateral surfaces is called angle of prism (∠A). A glass prism is a transparent object having two triangular ends and three rectangular sides. Question 21: At this angle , we can In an experiment to trace the path of a ray of light through a glass prism for different values of angle of incidence a student would find that the emergent ray: (c) sin r /sin i              (d) sin r /sin e Question 2: (a) 0° to 30°        (b) 30° to 60° Fix two more pins, at points R and S vertically such that the feet of pins at R and S appear to be on the same straight line as the feet of the images of the pins P and Q when viewed through the face AC of the prism. Question 6: In an experiment to trace the path of a ray of light through a glass prism for different values of angle of incidence a student would find that the emergent ray: View Answer The speed of light in air and glass is 3 × 1 0 8 m/s, and 2 × 1 0 8 m/s respectively. Answer: Question 3: (a) blue light is deviated more than indigo light (c) Question 11: Name the atmospheric refraction that causes splitting of white light. Practice: The refraction of light through the human eye. The colour of light that travels fastest in air is Draw a thin line XY at the middle of the paper. Samas in Hindi | समास परिभाषा व भेद और उदाहरण – हिन्दी व्याकरण, Sandhi in Hindi | संधि की परिभाषा, भेद और उदाहरण – हिन्दी व्याकरण, Ras in Hindi | रस के परिभाषा, भेद और उदाहरण – हिन्दी व्याकरण, Karak in Hindi | कारक परिभाषा, भेद और उदाहरण – हिन्दी व्याकरण, Visheshan in Hindi | विशेषण शब्द (Shabd), भेद (Bhed), प्रकार और उदाहरण – हिन्दी व्याकरण, Medical Fitness Certificate | Samples, Guidelines, Contents and Templates, Pratyay in Hindi प्रत्यय | प्रत्यय परिभाषा, भेद और उदाहरण – हिन्दी व्याकरण. Fix two pins at a distance of 5 cm from each other on the line PE as shown in the figure, later mark these points of pins as P and Q. the light approximately. The angle of deviation increases if the angle of incidence is further increased. Question 7. Question 6. (c) In an experiment to trace the path of a ray of light passing through prism, the correct measurement of angle of incidence (i) and angle of refraction (r) is shown in the diagram. This is because blue colour has lower wavelength and is much more by the air molecules. The phenomenon of bending of light from its straight path on the separation of two optical media is known as refraction of light. It is only the blue light which has shorter wavelength that is scattered most by the air molecules in the atmosphere. 90°. What is refractive index? (b) To get the measurable angle of deviation. Explanation: Because of the different indices of refraction for the different wavelengths of visible light, the angle of deviation varies with wavelength. Question 19: Since the refracting surfaces are not parallel, therefore, the emergent ray and incident ray are not parallel to one another. The phenomenon due to which the thin films of oil show colours is (d) depends on the angle of incidence. Questions based on Procedural and Manipulative Skills Question 31: In this case the sunlight is refracted downwards and because of this sun appears to be raised above the horizon than it actually is. (a) decreases to its minimum value the prism travels parallel to the base of the prism. Marriage Certificate Online | Application Process, Documents Required, How To Apply for Marriage Certificate Online? The incident ray changes its path as it gets deviated, due to refraction. Light rays always propagate in a rectilinear path. The correct observation made is: On increasing the angle of incidence in a prism experiment the emergent angle will: (a) (d) none of these. (c) smaller than angle of incidence A graph is drawn by taking the angle of incidence ‘i’ in the X-axis, and the angle of deviation ‘d’ along the Y-axis. Explanation: The grazing emergence is possible only when the angle of Explanation: (d) none of these (a) 90°                             (b) 0° Study the following diagrams in which the path of a ray of light passing through a glass prism as traced by four students P, Q, R and S is shown: Dispersion of White Light by a Glass Prism. (b) decrease emerging at the second surface in a grazing manner, damaging angle is equal to Explanation: What is the cause of rainbow? The angle of prism is 60° and the minimum deviation it produces is of 30°. bends at different angle and split into different colours when it passes through a glass prism. In which of the four cases one is likely to get the best result? Answer: Question 24: Question 33: But after passing through the Question 6: called the grazing emergence. In this case the Question 3: (d) all of these (b) the incident angle of the light ray (a) periscope                   (b) telescope Inside the prism, the light ray strikes the surface with a Which of the following figures shows the correct path of a ray of light traveling from air into a prism? Question 30: When the angle of the prism is constant we can write that the Student C —> looked at heads of P1 and P2 while placing P3 and feet of P3 while placingP4. Answer: If KL be a monochromatic light falling on the side AB, it is refracted and travels along LM. emerges out from the other surface. (c) same in both the medium It has wave nature and also particle nature in the form of a photon. Proper arrows should be drawn for the incident ray, refracted ray and emergent ray. For the refraction of a ray of light through a glass prism, the path of a ray of light is shown below: He found that if a beam of white light is passed through glass prism then it will split in to seven colours. Throwing light in various random directions on various types of suspended particles is called scattering of light. In case of a glass slab, when white light passes through it then the light bends into very small angle and splits only by very small amount. The splitting of white light into its constituent colours is called dispersion of light. The angle is formed between the normal ray, and the incident, emergent and combined rays respectively. It is denoted by δ or D. Drawing: Let the ray NʹR due to extension backward meet with NQOʹ at point O. minimum value of deviation is called angle of minimum deviation. Which light bends the least and the most? Answer: ray to strikes the surface of the prism. Do you know what relative refractive index is? [NCERT] Answer: Since, the two faces of glass slab are parallel to each other. When white light passes through first prism it disperses the light into seven colours and when this beam of light enters the second prism which is placed in an inverted position, a white light is obtained when it comes out of the second prism. (c) The dispersion of white light happens because the angle of refraction of lights of different colours is different while passing through the transparent medium. Question 2: Refraction of Light Through a Prism Experiment. (c) X, N, Z              (d) X, M, Z Answer: Repeat the experiment for more angle of incidence preferably between 30° and 60°. Dispersion is the phenomenon of splitting of light into its constituent colors or wavelengths. The refraction of light in glass prism is different from a glass slab. The angle of incidence as well as the angle of emergence at continue in its path without any change in its path. Why does white light split into different colours when passes through a glass prism? Student B —> looked at feet of P1, P2 while placing P3 and P4. Red light will travel fastest in air, because red light has the least refractive index. (d) angle of incidence. This angle is called the angle of deviation (∠D). What happens to a ray of light when it passes from an optically rarer medium to a denser medium? (d) violet light is deviated more than blue light. This is also called angle of prism or apex Answer: Answer: Here angle ∠SOL represents the angle of deviation for that ray. Different wavelengths of light refract differently, and the refractive index varies with the wavelength of light used. (d) equal to zero. Hence, the refracted light rays suffer equal amount of deviation. It is denoted by δ or D. Definition of the angle of deviation: If the incident ray on the prism is extended forward and the emerging ray from the prism is extended backward, then the angle between these two rays is called the angle of deviation or deviation. Answer: Answer: Fix a white sheet of paper on a drawing board. Light can behave in many ways as it has dual nature. [NCERT] Answer: When a light ray passes through glass prism, first it travels from rarer to denser medium so, it bends towards the normal or base of prism. Question 3: Two dots P1 and P2 shown in each of the following diagrams I, II, III, and IV denote the position of two pins in respect of distance and direction for performing an experiment on tracing the path of a ray of light passing through a glass prism. Ans- Ray optics is the other name for geometric optics. Refractive index n = sin i / sin r It gets refracted traveling along the path LM. Incident ray will make an angle of incidence with the normal. Practice: An experiment with light rays and a prism. (c) Draw a thin line NEN normal (perpendicular) to face AB of the prism. In this situation, tiny raindrops act as glass prism splitting the white sunlight. Refraction of Light Through a Prism Experiment. (d) Question 4: Answer: The feet of the pins may not be in same straight line. The angle of incidence should be between 30° and 60°. (c) dispersion               (d) all of these derive the equation for the refractive index of a prism with respect to the List the factors on which the angle of deviation through a prism depend. nonparallel surfaces. The value of angle of deviation is ………… for the angle of incidence ………………. The angle of deviation first decreases with the increase in angle of incidence ∠i. Fix a white sheet on a drawing board using drawing pins. In 1665, Isaac Newton discovered that white light consists of seven colours. A prism is usually made from materials like glass, plastic, and fluorite. Let KL be a monochromatic beam of light that falls on the side AB of the prism. Answer: Question 23: This (b) Answer: The range of angle of incidence is 30° to 60°. Therefore, stars appear bright at one moment and dim in another. State the laws of refraction. The light from stars is refracted as it comes down into earth’s atmosphere. Explanation: Answer: (c) Spectrum of white light: The band of seven colours formed when a beam of white light is passes through a glass prism is called spectrum of white light. The maximum colour in the band is Answer: Calculation of deviation: Suppose ∠PQN = i1, ∠OʹQR = r1, ∠SRNʹ = i2, and ∠OʹRQ = r2. What is refraction of light? equal to refractive index of glass prism with respect to medium. Angle of deviation is the bending ability of light when it travels from different media. If there is a rise in the angle of incidence, then the angle of deviation ‘d’ decreases and reaches a minimum value.