An important application of interference in thin films is the formation of Newton’s rings. When a plano-convex lens is placed on the top of a flat glass surface a thin air film is formed between the two surfaces as shown in the figure. accha kar rahe hain. Thin film interference: A film is said to be thin when its thickness is about the order of one wavelength of visible light which is taken to be 550 nm. Q.What if sodium light is replaced with white light? When a plano convex lens of long focal length is placed over an optically plane glass plate, a thin air film with varying thickness is enclosed between them. 1. Change ), An ongoing discussion about SAP infrastructure. Newton observed these rings when placing a spherically shaped piece of glass (a lens) touching a flat piece of glass. Q.What if the glass plate is replaced with plane mirror? << Q.What will happen if few drops of liquid is introduced between the lens and glass? Newton's ring experiment 1. Ans.) View all posts by Divya Prakash Srivastava. In 1717, Sir Isaac Newton studied the rings pattern generated due to interference of light. Q.Why do rings get closer as their order increases? The interference is between the reflexions from twoneighboring surfaces; 2. 1. endobj /Type /Pages Theory of Newton’s Ring Circular interference fringes can be produced by enclosing a very thin film of air or any other transparent medium of varying thickness between a plane glass plate and a convex lens of a large radius of curvature. Intensity of fringes also depend upon the air column between lens and the base. … Click "Submit" button to verify the answers given, click on simulator button to skip the test and go to simulator. Ans : The path difference along the circle is constant that’s why the rings are circular in this experiment. isi chij ki to talas hai . EXPERIMENTAL SET UP The cross wire of the microscope is fixed at a particular dark ring, say, nth and reading is noted on microscope. rays of same frequency and constant phase difference. )Travelling microscope,a sodium lamp,newtons ring apparatus,a spherometer, a cone lens of short focal length . A.Then we will not get interference fringe because the intensity of light reflected from mirror will be so great that it won’t be visible and we will get uniform illumination. i like it ,keep it up, The knowledge is well presented and meaningful thank you, It was very useful and helped clear the concept, Thanks for this viva and the site as well, Super sir!! (determination of knee voltage, zener voltage and forward resistance) … Thank you! The thickness of the air film is zero at the point of contact and gradually increases outwards from the point of contact. What happened if I replace the plano-convex lens with the plano-concave lens? @~ (* {d+��}�G�͋љ���ς�}W�L��$�cGD2�Q���Z4 E@�@����� �A(�q`1���D ������`'�u�4�6pt�c�48.��`�R0��)� newton ring experiment viva questions wit answers Important: Use custom search function to get better results from our thousands of pages Use " " for compulsory search eg:"electronics seminar" , use -" " for filter something eg: "electronics seminar" -"/tag/" (used for exclude results from tag pages) EXPERIMENT: 4 Object: To find the wavelength of Sodium light by Newton’s ring. newtons rings • 19k views. 2 0 obj Q.What will happen if we replace the lens with plane glass? Newton gave the following list of colours from the centre outwards: First order: Black, blue, white, yellow, orange, red. Apparatus used: A Plano convex lens of large radius of curvature, optical arrangement for Newton’s rings, plane glass plate, sodium vapour lamp and traveling microscope. A.The diameter of dark rings is proportional to the square root of natural numbers while bright rings are proportional to the square root of odd natural numbers hence the don’t increase at the same rate. very good sir. The radius of curvature R of the spherical body can be determined from the radii r of the interference rings as long as the wavelength λ is known. /Kids [42 0 R 68 0 R 94 0 R 123 0 R 156 0 R 189 0 R 220 0 R] ( Log Out /  stream Experimental arrangement for observing Newton's rings: Let us consider a system of plano-convex lens of radius of curvature R placed on flat glass plate it is exposed to monochromatic light of wavelength λ normally. Would the shape and the order of rings change? Newton was the first to observe the Newton’s rings Sir Isaac Newton (1642-1727): While the fall of an apple remains an ordinary phenomenon for a layman, it was not so for Newton. A.Then we will have dark and bright fringes in shape of a line. The illumination is from above, leading to a dark central region. A.They are formed as a result of interference between light waves reflected from the upper and lower surfaces of the… endobj Formula used: … A.The diameter of the rings will decrease because the diameter of the rings is inversely proportional to the refractive index. >> The thickness will decrease ,shape will not change, the rings will come close as diameter decreases. A.They are formed as a result of interference between light waves reflected from the upper and lower surfaces of the air film developed between the convex surface of plano convex lens and plane glass plate. >> Due to this thin film of air a path difference occurs in the waves which reflect from the lower surface of the lens and the top surface of the glass plate. What happened if we replaced yellow light with green light? Thank you! A.At the point of contact the path difference is zero but one of the rays is reflected so the effective path difference becomes  λ/2 thus the condition of minimum intensity is created hence it is a dark spot. Q.How are Newton's rings formed? When light is incident on such a film, a small portion gets reflected from the upper surface and a major portion is transmitted into the film. Q. The air film formed is wedge shaped locus of point of intersection is equal to the thickness of circles . at 19:05. Fill in your details below or click an icon to log in: You are commenting using your WordPress.com account. After going through the theory and pretest, click the "Simulation" tab 2. View all posts by Divya Prakash Srivastava, energy, engineering, examination, experiment, information, Physics, physics lab, practicals, solar cell, viva, vivavoce, engineering, juet, newton's ring, physics, practicals, questions, viva, vivavoce. The balance of good and bad awaits your vision. Newton’s Rings and Determination of the Wavelength of Light Newton’s Rings. ( Log Out /  Newton's rings is an interference pattern caused by the reflection of light between two surfaces - a spherical surface and an adjacent flat surface. Two salient reasons: 1. Popular Searches: newton raphson jacobian matrix ppt, newton raphson method matlab code iee 5 bus system, viva questions with answers for torsional pendulum experiment in physics, project report examples newton xmm, diffraction grating experiment viva questions with answers, ultrasonic interferometer experiment viva questions pdf, what is ring detect circuit in modemviva questions and … ?���:��0�FB�x$ !���i@ڐ���H���[EE1PL���⢖�V�6��QP��>�U�(j Share to Twitter Share to Facebook Share to Pinterest. What do you mean by interference of light? Very useful stuff. (a) Experimental set-up (b) Newton’s rings Figure 1 In general, the path di erence between the re ected light beams which are undergoing interference (for oblique incidence) is given by = 2 tcos 2; (1) where additional path di erence of 2 is because one of the interfering beam is re ected from lm to glass surface. A.Alternate dark and bright rings formed due to presence of air film when plano convex lens is placed on glass plate is called newtons rings. This can be seen from the formula r 2 = (m + ½) λa, (3), as r 2 α λ 1. Change ), You are commenting using your Facebook account. Newton's rings interference pattern created by a plano-convex lens illuminated by 650 nm red laser light, photographed using a low-light microscope. *1 J�� "6DTpDQ��2(���C��"��Q��D�qp�Id�߼y�͛��~k����g�}ֺ ����LX ��X��ň��g`� l �p��B�F�|،l���� ��*�?�� ����Y"1 P������\�8=W�%�Oɘ�4M�0J�"Y�2V�s�,[|��e9�2��s��e���'�9���`���2�&c�tI�@�o�|N6 (��.�sSdl-c�(2�-�y �H�_��/X������Z.$��&\S�������M���07�#�1ؙY�r f��Yym�";�8980m-m�(�]����v�^��D���W~� ��e����mi ]�P����`/ ���u}q�|^R��,g+���\K�k)/����C_|�R����ax�8�t1C^7nfz�D����p�柇��u�$��/�ED˦L L��[���B�@�������ٹ����ЖX�! Q. 12.) Sorry for my bad grammar. Life is all about Experiences. NEWTON’S RINGS - Q1 1) In the Newton’s ring experiment, how does interference occur? A.It turns the light rays coming from an extended source to ninety degrees and so the rays fall normally on the plano convex lens. Email This BlogThis! Viva Voce for by Newton’s Ring. Ans: Diameter of a ring depends on the wavelength of light used, refractive index of the medium between lens and glass plate, order of the ring and radius of curvature of Planocovex lens. Let’s consider a dark ring with radius r at a point where the separation is t. The right angled triangle shown in red has a height R–t so Pythagoras’ theorem gives us. In this experiment Newton’s rings are investigated using monochromatic light trans-mitted through the apparatus. %PDF-1.7 The global geometry of Newton’s rings. The experimental setup: a convex lens is placed on top of a flat surface. Q.what is the function of the 45° inclined glass plate? /N 3 ADD COMMENT 0. written 4.3 years ago by vermavarsha432 • 130: The path difference between the reflected ray and incident ray depends upon the thickness of the air gap between lens and the base. They arise from the interference of light. Tq u air thanks a lot. By MONOCHROMATIC SOURCE, we mean a light source which emits particle of particular wavelength and not many wavelengths. A.Then the rings will be of smaller diameter and there is chance of error while taking the readings. When the two or more waves superimpose over each other, resultant intensity is modified. Such fringes were first obtained by … 4. �@���R�t C���X��CP�%CBH@�R����f�[�(t� C��Qh�z#0 ��Z�l�`O8�����28.����p|�O×�X 11.19 Refractive Index of a Liquid using Newton’s Rings 242 11.20 Newton’s Rings with Bright Centre due to Reflected Light 244 11.21 Newton’s Rings with White Light 244 11.22 Interference Filter 244 11.23 Object (Measurement of wave length of sodium light by Newton’s Rings) 245 11.24 Viva-Voce 248 12. �MFk����� t,:��.FW������8���c�1�L&���ӎ9�ƌa��X�:�� �r�bl1� Q.What are Newton's Rings? [/ICCBased 3 0 R] ( Log Out /  3 0 obj Newton's rings are a fun demonstration of the wave nature of light, and also of the fact that white light is made up of many components of different wavelengths. Excellent questions we can score full marks in viva through this questions. Newton's Ring Experiment Procedure. {{{;�}�#�tp�8_\. In this experiment, we have taken sodium lamp as the monochromatic source. To determine the wavelength of the given source. realli it was very awesome,very helpful in enhancing and clearing the concepts.. best website for viva 1 Presented by- Group 1 EE Batch 1 2. Labels: NEWTON’S RINGS. /Filter /FlateDecode Newtons Ring Experiment Viva. The modification in the distribution of intensity in the region of superposition is called interference. Det erminat ion of t he wavelengt h of a monochromat ic source by using Newt on’s Ring experiment T he key idea behind Newt on’s Rings experiment is t he t hin f ilm f ormat ion bet ween a plane-convex lens and a glass plat e. Change ), You are commenting using your Twitter account. When the air film is … The phenomenon of interference of light waves is obtained from monochromatic and coherent rays i.e. /Count 7 Ans : Alternate dark and bright rings with central dark spot are called newton’s rings. ( Log Out /  The experimental setup for Newton’s ring is shown in the figure above. R 2 = (R − t) 2 + r 2 which gives R 2 = R 2 − 2Rt + t 2 + r 2 and so 2Rt = t 2 + r 2. Q.What will happen if we use a lens of small radius of curvature? The … ya,dear fellow scientists i appreciate your support and comments,so keep it up. These concentric rings are known as " Newton's Rings ". Newton’s ring apparatus Aim of the experiment To study the formation of Newton’s rings in the air-film in between a plano-convex lens and a glass plate using nearly monochromatic light from a sodium-source and hence to determine the radius of curvature of the plano-convex lens. newtons ring experiment viva questions, viva questions on carey foster bridge experiment, fresnel biprism experiment viva questionsseminar report nanotechnology 2050, newtons ring experiment viva questions with solutions pdf, bhel davr manual pdfe examination system109619solar cell experiment viva question ans, michelson interferometer experiment viva questions, viva for flywheel experiment, A.This is so because the air film formed is wedge shaped and loci of points of equal thickness are circles concentric with point of contact. Physics Lab(15PHYL17/27) Viva Questions: EXPERIMENTS: 1. 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