5.Slide the microscope to the left till the cross wire lies tangentially at the center of the 20th dark ring. R2 = R2 − 2 Rt + t2 + r2 and so. O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers. 1000 1000 1055.6 1055.6 1055.6 777.8 666.7 666.7 450 450 450 450 777.8 777.8 0 0 Spectrometer LIST OF EXPERIMENTS 1. 1. Syllabus & Class Notes. Advanced Engineering Mathematics Book-1st year B.Tech engineering free Download pdf Higher Engineering Mathematics E-book by B V Ramana, Tata McGraw-Hill-free download in pdf Home 1st sem 1st sem physics Notes 2nd sem b.tech b.tech 1st year btech 1st sem btech first sem physics practical copy Physics practical copy rtu utd Physics Practical Copy of B.TECH 1st SEM/Year Complete - rtu The ray treatment of light is called geometrical optics as distinct from physical optics, which attempts to explain the objective phenomena of light. /FontDescriptor 18 0 R /Name/F3 In order to determine the refractive index of liquid the Newton’s ring experiment is first performed for the air medium and the difference in the square of the … • Implied from 3rd law. 556 333 1000 556 556 333 1000 667 333 1000 0 0 0 0 0 0 333 333 350 556 1000 333 1000 Ans : The basic principle of newtons rings experiment is Interference phenominan. If the radius of curvature of plano-convex lens is much greater than distance ‘r’ and the system is viewed through the above, the pattern of dark & bright ring is observed. For n-th (bright or dark) ring (see Fig. Determination of Velocity of Ultrasonic waves in a given liquid using Ultrasonic Interferometer. These rings are similar, yet distinctly different from conventional Newton’s rings. 5{bB*��k��_)r��T˷ +�h�����E�鄎 p7��O]ƿKGD����ƽt��k�F�8����fb���|XjB�J#峊�-,ia��!lw�'G��`Xӱ�h������.�r�ي���$;�U��X�Tz�.������� bv�I���9�.�&6�G�a�v�#f�Y��S`�s�R�L/)����X��f�ܳ7`�j������� �����q�3�[` EN{0R}k��m�]E�C�V{���N�9=�����h�qS��~\Z�Z. Substitute the values in the following equation. Wie muss Abb. Physics with animations and video film clips. Newton 's ring method; Fresnel's Bi-Prism; Michelson Interferometer; Optics-Diffraction and Dispersion. Ans : … 833 556 556 556 556 333 500 278 556 500 722 500 500 500 334 260 334 584 0 0 0 222 /Encoding 7 0 R /FirstChar 33 Newton's ring pattern is a result of interference between the partially reflected and partially transmitted rays from the lower curved surface of plano-convex lens and upper surface of the plane glass plate. /FontDescriptor 12 0 R 19 0 obj /LastChar 255 2), we also have 2 2 4 tR D n (3) where D n = the diameter of the n-th ring and R = the radius of curvature of the lower surface of the plano-convex lens. 2 0 obj ... Engineering Category (1) relates science concept to engineering Keywords cooling, exponential, heat, Newton, temperature, … 6.2: Solving Problems with Newton's Laws (Part 1) Newton’s laws of motion can be applied in numerous situations to solve motion problems. /Subtype/Type1 1.1 Das Newtonsche Grundgesetz Einsetzen in die Bewegungsgleichung in x-Richtung führt auf: Die Beschleunigung hängt nicht vom Gewicht der Kommode ab. �(�Ո���9�t��{!o~���h����q���,��1u��:Q7�c{�3��,�:c�ǧ�?�F�XD��C������צ��}U�x���Ѹ� endobj >> Apparatus: Traveling microscope, sodium vapour lamp, plano-convex lens, plane glass plate, magnifying lens. Physclips provides multimedia education in introductory physics (mechanics) at different levels. 722 722 722 722 722 611 556 500 500 500 500 500 500 722 444 444 444 444 444 278 278 278 500 500 500 500 500 500 500 500 500 500 333 333 570 570 570 500 930 722 667 722 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. Hi friends Here i am uploading some amazing lecture notes/eBook for first year engineering subject - Physics: Waves and Oscillations. Reference . 4 0 obj Physik . /FirstChar 33 /Type/Font Find the slope and substitute it in the following formulae which gives wavelength of light ME101: Engineering Mechanics Mechanics: Oldest of the Physical Sciences Archimedes (287-212 BC): Principles of Lever and Buoyancy! Important Questions . Figure 3: A slightly convex lens is placed above an optical flat. Lec : 1; Modules / Lectures. Why? 889 667 611 611 611 611 333 333 333 333 722 722 722 722 722 722 722 564 722 722 722 Tech. /Type/Encoding 722 722 667 611 778 722 278 500 667 556 833 722 778 667 778 722 667 611 722 667 944 To determine the wavelength of sodium light using plane diffraction … A thorough understanding of physics at the lower-division level, including a basic working knowledge of the laws of mechanics, is assumed. 147/quotedblleft/quotedblright/bullet/endash/emdash/tilde/trademark/scaron/guilsinglright/oe/Delta/lozenge/Ydieresis • Objects react with the same force exerted on them. 589.1 483.8 427.7 555.4 505 556.5 425.2 527.8 579.5 613.4 636.6 272] Lec : 1; Modules / Lectures. 2 Rt = t2 + r2. • Classical Electrodynamics A lecture note style textbook intended to support the second semester (primarily the dynamical portion, little statics covered) of a two semester course of graduate Classical Electrodynamics. /BaseFont/NATTHG+CMMI12 >> Greater the mass of a body greater will be its inertia or vice-versa. Hint: r 2 = (2n – 1) λ R / 2. λ= 5760 A . 333 722 0 0 722 0 333 500 500 500 500 200 500 333 760 276 500 564 333 760 333 400 Travelling Microscope IV. ….2.29. /Widths[333 500 500 167 333 556 222 333 333 0 333 584 0 611 500 333 278 0 0 0 0 0 /LastChar 255 /BaseFont/PDPLMD+NimbusRomNo9L-Medi 10.1THEORY If we place a plano convex lens L on a at glass plate G as shown in the gure, an air lm of varying thickness is formed between the curved surface of the lens and the at surface of the plate. 0 0 0 0 0 0 0 333 191 278 278 355 556 556 889 667 222 333 333 389 584 278 333 278 << When viewed with monochromatic light, Newton's rings appear as a series of concentric, alternating bright and dark rings centered at the point … Vernier Calipers III. 500 333 944 0 0 667 0 333 556 556 556 556 260 556 333 737 370 556 584 333 737 333 The speed of light is very large B. light is a transverse wave C. light is electromagnetic in character D. Light is a wave phenomenon 2. Travelling Microscope IV. /Widths[333 556 556 167 333 611 278 333 333 0 333 564 0 611 444 333 278 0 0 0 0 0 Tech. They arise due to interference in light reflecting from the upper and low-er boundaries of an air gap between two very nearly parallel surfaces. Mechanics is a branch of the physical sciences that is concerned with the state of rest or motion of bodies subjected to the action of forces. 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 606.7 816 748.3 679.6 728.7 811.3 765.8 571.2 ENGINEERING PHYSICS LAB MANUAL (As per 2017 Academic Regulation) Common to all branches of B. /Differences[1/dotaccent/fi/fl/fraction/hungarumlaut/Lslash/lslash/ogonek/ring 11/breve/minus endobj Auf dieser Platte liegt wiederum eine schwach gekrümmte Linse. Physclips provides multimedia education in introductory physics (mechanics) at different levels. 489.6 489.6 489.6 489.6 489.6 489.6 489.6 489.6 489.6 489.6 489.6 272 272 761.6 489.6 Frosted plastic is placed in front of the laser to diffuse the light. 947.3 784.1 748.3 631.1 775.5 745.3 602.2 573.9 665 570.8 924.4 812.6 568.1 670.2 761.6 679.6 652.8 734 707.2 761.6 707.2 761.6 0 0 707.2 571.2 544 544 816 816 272 /Type/Font /Subtype/Type1 Subject Area(s) Measurement, physical science, physics Associated Unit None Associated Lesson None Activity Title Newton’s Law of Cooling Header None ... which verifies Newton’s result. 16 0 obj Determination of … 278 556 556 556 556 556 556 556 556 556 556 278 278 584 584 584 556 1015 667 667 onssymmetrie der Anordnung beobachtet man helle und dunkle Interferenzringe um ein größeres dunkles Zentrum herum, die . 472.2 472.2 472.2 472.2 583.3 583.3 0 0 472.2 472.2 333.3 555.6 577.8 577.8 597.2 Experiment 4 - To determine the wavelength of Monochromatic light (sodium light) by Newton’s Ring Experiment 5 - To determine the wavelength of sodium light source using plane transmission grating Experiment 6 - To verify Inverse square law of … Displacement of Fringes, Fringes, Interference of Fringes, Interference of Light . /Widths[791.7 583.3 583.3 638.9 638.9 638.9 638.9 805.6 805.6 805.6 805.6 1277.8 Determination of Velocity of Ultrasonic waves in a given liquid using Ultrasonic Interferometer. Physics with animations and video film clips. Thin film interference with films of varying thickness (Newton’s rings): Rings are fringes of equal thickness. %PDF-1.2 Newtons Ring. Some problems contain multiple force vectors acting in different directions on an object. x��ko7��~��h���=�h����~Pd��U�:��4���A�C�ʛ�Cb[��{�3������l~o�����j� ~����������y�����j7��w��Ļ�뫛�PZ�/�����O [���GS� ��WR��J�?���w ��ko���q���շ ���Eq��l���H��m�P��,`���p�VA��W�~#vItW"� ]�����V�/F[~�����"|����t'nz���:��e;��|Q The light goes through the convex lens. On neglecting t2, equation (3) reduces to D n 2 = 8tR (4) From equations (1) and (4), we get, R 2 1 D 4 n 2 n , for n-th bright ring (5) R 2 1 Introduction Recently, a novel method has been proposed and setup in our undergraduate laboratory to determine the wavelength of laser light using modified Newton’s rings. <>/OutputIntents[<>] /Metadata 714 0 R>> 722 1000 722 667 667 667 667 389 389 389 389 722 722 778 778 778 778 778 570 778 /Encoding 7 0 R The diameter of 811′ dark ring in the transmitted system is 0.72 cm. Die Newtonschen Ringe sind nicht nur bei Reexion sondern auch in Durchsicht zu beob-achten. Aim: To revise the concept of interference of light waves in general and thin-film interference in particular. R. C. Hibbler, Engineering Mechanics: Principles of Statics and Dynamics, Pearson Press, 2006. <>/XObject<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 595.44 841.68] /Contents 4 0 R/StructParents 0>> 334 405.1 509.3 291.7 856.5 584.5 470.7 491.4 434.1 441.3 461.2 353.6 557.3 473.4 Displacement of Fringes, Fringes, Interference of Fringes, Interference of Light. 500 500 500 500 333 389 278 500 500 722 500 500 444 480 200 480 541 0 0 0 333 500 Thermal Physics. Figure 3: A slightly convex lens is placed above an optical flat. In Newton's Ring experiments , the diameter of bright rings is proportional to A. 667 1000 722 667 667 667 667 278 278 278 278 722 722 778 778 778 778 778 584 778 Some problems contain multiple force vectors acting in different directions on an object. 14.5 Newton’s rings As shown in Fig. Newtonschen Ringe. (9) Which light do u use in this experiment ? In the traditional version of Newton's Rings, a slightly convex lens is placed above a flat glass plate or optical flat. Experiment8. 13 0 obj Square root of Odd Natural numbers B. Aim: To determine the wavelength of sodium light by Newton’s Ring method. prepared manual for the experiments in the Engineering Physics course. /FontDescriptor 15 0 R Physics 2107 Newton’s Rings Experiment 5 In this experiment you will study the phenomenon of Newton’s Rings, and use it to (A) Measure the wavelength of light, and (B) The refractive index of water. << 761.6 489.6 516.9 734 743.9 700.5 813 724.8 633.9 772.4 811.3 431.9 541.2 833 666.2 Newton observed these rings when placing a spherically shaped piece of glass (a lens) touching a flat piece of glass. 564 300 300 333 500 453 250 333 300 310 500 750 750 750 444 722 722 722 722 722 722 Apparatus) on the wooden platform to form the Newton’s Ring. 0 0 0 0 0 0 0 333 278 250 333 555 500 500 1000 833 333 333 333 500 570 250 333 250 Simulator . This site will allow you to access content of engineering Physics syllabus of Peoples University,related assignments, attendence and stay informed in recent activities in physics. 667 667 611 278 278 278 469 556 222 556 556 500 556 556 278 556 556 222 222 500 222 Problem 8. /Type/Font 791.7 777.8] /LastChar 196 for the engine for the ring. Newton’s laws of motion can be applied in numerous situations to solve motion problems. It Mostly Revolves Around Newton’s 1st Law of Motion 90% of the questions that I ask students regarding forces have to do with Newton’s 1st Law of Motion. /LastChar 196 stream endobj physics 111N 33 two-dimensional equilibrium! Start your free trial. Rigid-body Mechanics ME101 Statics Dynamics Deformable-Body Mechanics, and 1.1 a, b and c). 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. Newton’s rings Aim of the experiment: To observe Newton rings formed by the interface of produced by a thin air film and determine the radius of curvature of a plano-convex lens. Polarization of light I; Polarization of light II; EM Theory. /Name/F5 2. The apparatus is set up as shown (Fig. A monochromatic source of light S … Light, interference, thin films. 1 0 obj Introduction; Postulates of Kinetic Theory of Gases; Pressure Exerted by an Ideal Gas; Kinetic Energy ad Temperature; ... Fresnel Biprism and Newton's ring; Michelson interferometer; Febry-Perot Interferometer; Engineering … Light from a Sodium lamp S falls on a at glass plate P placed at 45 with respect to the incident beam. The phenomenon of interference of light waves is obtained from monochromatic and coherent rays i.e. (Refer Fig. 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. 833.3 1444.4 1277.8 555.6 1111.1 1111.1 1111.1 1111.1 1111.1 944.4 1277.8 555.6 1000 Seite 2 . Newton's rings is analysed as an interference pattern and we derive the equation relating the len's radius of curvature to the radii of the dark rings. /Length 1922 6.3: Solving Problems with Newton's Laws (Part 2) Physics Laboratory IIT Delhi the thickness of the air gap. Fig 5.19 shows an experimental arrangement for producing and observing Newton’s rings. 400 584 333 333 333 556 537 278 333 333 365 556 834 834 834 611 667 667 667 667 667 you are here->home->Physical Sciences->Laser Optics Virtual Lab->Newton's Rings-Wavelength of light.. Newton's Rings-Wavelength of light.. Optics by Ajay Ghatak. 272 272 489.6 544 435.2 544 435.2 299.2 489.6 544 272 299.2 516.8 272 816 544 489.6 Theory . In the Newton’s rings arrangement, the radius of curvature of the curved surface is 50 cm. 761.6 272 489.6] Lab Manual of Physics lab physics manual-1.pdf File size: 841 KB File content type: application/pdf Category: Practical Files. endobj 380.8 380.8 380.8 979.2 979.2 410.9 514 416.3 421.4 508.8 453.8 482.6 468.9 563.7 Newtonsche Ringe treten bei Interferenz von Licht an der dünnen Schicht zwischen einer schwach gewölbten Linse und einer Glasplatte auf (siehe Abb. 722 611 556 722 722 333 389 722 611 889 722 722 556 722 667 556 611 722 722 944 722 389 333 722 0 0 722 0 333 500 500 500 500 220 500 333 747 300 500 570 333 747 333 In rare cases where the earth’s motion is important, we take the stars far from the solar system to be fixed. Vernier Calipers III. /Encoding 7 0 R Newton’s rings method. When a plane-convex lens of long focal length is placed on a plane glass plate, a thin film Monochromatic light is used to illuminate the lenses. Find the tension in each chain, assuming their masses are negligible. 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 458.3 458.3 416.7 416.7 Title: EXPERIMENT NO Author: … physics. /Type/Font Newton's rings is analysed as an interference pattern and we derive the equation relating the len's radius of curvature to the radii of the dark rings. Engineering Physics 1 Interference and Diffraction 1. /Name/F1 << physics 111N 13 Newton’s second law “ The acceleration of an object is directly proportional to the resultant force acting on it and inversely proportional ... ring. Theory of relativity. 299.2 489.6 489.6 489.6 489.6 489.6 734 435.2 489.6 707.2 761.6 489.6 883.8 992.6 �q^͞��a�F�W����m:���a%��r��5 The radius of the rings: The global geometry of Newton’s rings. Andy Ruina and Rudra Pratap , Introduction to Statics and Dynamics , Oxford University Press, 2011. 6 Part 1. Newton’s rings method. >> A thin air film is formed between the plate and the lens. 3) Place the crosswire of the eyepiece of the traveling microscope on the tangent position of the 10th dark ring at the left position from the centre ring. 722 611 333 278 333 469 500 333 444 500 444 500 444 333 500 500 278 278 500 278 778 x�uXK��4��+|�.&’�ׁ�PK��3UP�p�8J�Z�6������K���^b��j���V+A��8���5����_t�set��`�M�lOѿO�!��*/�Q�Le9�#_�����@�@'����,�c`�Li���1Ъ,��f9��VYC���j�5�b�����c\E&`�U��T�2E��\�L���E Z��Gc��g7���t�i���eXE&?Gچ�u�~>�~�y�{�?�<. Subject Area(s) Measurement, physical science, physics Associated Unit None Associated Lesson ... which verifies Newton’s result. 161/exclamdown/cent/sterling/currency/yen/brokenbar/section/dieresis/copyright/ordfeminine/guillemotleft/logicalnot/hyphen/registered/macron/degree/plusminus/twosuperior/threesuperior/acute/mu/paragraph/periodcentered/cedilla/onesuperior/ordmasculine/guillemotright/onequarter/onehalf/threequarters/questiondown/Agrave/Aacute/Acircumflex/Atilde/Adieresis/Aring/AE/Ccedilla/Egrave/Eacute/Ecircumflex/Edieresis/Igrave/Iacute/Icircumflex/Idieresis/Eth/Ntilde/Ograve/Oacute/Ocircumflex/Otilde/Odieresis/multiply/Oslash/Ugrave/Uacute/Ucircumflex/Udieresis/Yacute/Thorn/germandbls/agrave/aacute/acircumflex/atilde/adieresis/aring/ae/ccedilla/egrave/eacute/ecircumflex/edieresis/igrave/iacute/icircumflex/idieresis/eth/ntilde/ograve/oacute/ocircumflex/otilde/odieresis/divide/oslash/ugrave/uacute/ucircumflex/udieresis/yacute/thorn/ydieresis] ... A Handbook of Advance Practical Physics by C.R. Such fringes were first obtained by Newton and are known as Newton’s rings. /Subtype/Type1 /Widths[333 556 556 167 333 667 278 333 333 0 333 570 0 667 444 333 278 0 0 0 0 0 27 0 obj 597.2 736.1 736.1 527.8 527.8 583.3 583.3 583.3 583.3 750 750 750 750 1044.4 1044.4 * If you understand Newton’s 1st Law and what forces have to do with it, … /FirstChar 1 1277.8 811.1 811.1 875 875 666.7 666.7 666.7 666.7 666.7 666.7 888.9 888.9 888.9 7 0 obj 1. Man beobachtet zunächst mit dem freien Auge die Ringe. Engineering Physics I (Theory) (Web) Syllabus; Co-ordinated by : IIT Guwahati; Available from : 2009-12-31. letzte Änderung: 02.10.2017 . They are observed when light is reflected from a plano-convex lens of a long focal length placed in contact with a plane glass plate. >> endobj 25 0 obj /LastChar 196 734 761.6 666.2 761.6 720.6 544 707.2 734 734 1006 734 734 598.4 272 489.6 272 489.6 278 278 500 556 500 500 500 500 500 570 500 556 556 556 556 500 556 500] /FirstChar 1 Procedure . rays of same frequency and constant phase difference. Newton’s first law of motion 1. endobj Assignment . Physics Notes Class 11 CHAPTER 5 LAWS OF MOTION Inertia The property of an object by virtue of which it cannot change its state of rest or of uniform motion along a straight line its own, is called inertia. 722 722 667 333 278 333 581 500 333 500 556 444 556 444 333 500 556 278 333 556 278 <> ENGINEERING PHYSICS LAB MANUAL (As per 2017 Academic Regulation) Common to all branches of B. Background In this optics experiment, a convex lens is placed on a reflecting surface. Since the light re ... be shown from geometry that the diameter of the nth dark ring is given by, D2 n = 4 t(2R) = 4n R (10.3) Similarly for the (n+ m)th ring, D2 n+m = 4(n+ m) R (10.4) … 444 1000 500 500 333 1000 556 333 889 0 0 0 0 0 0 444 444 350 500 1000 333 980 389 699.9 556.4 477.4 454.9 312.5 377.9 623.4 489.6 272 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 >> a car engine of mass 500 kg hangs at rest from a set of chains as shown. When viewed with white light, the fringes are coloured (shown in the wrapper of the text book). Archimedes ( 287-212 BC ): pRiNcipLES of Lever and Buoyancy 5.19 shows an experimental arrangement for producing and Newton... Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers Measurement properties! On the glass plate G kept at 45o Lesson... which verifies ’... Gap between two very nearly parallel surfaces Physics course animations and video clips!, Measurement and properties to: European Journal of Physics LAB Physics manual-1.pdf File size: 841 KB File type. Ektierte, durch den halbdurchlässigen Spiegel, senkrecht nach oben austretende Licht mit Mikroskop! Used in many branches of B hängt nicht vom Gewicht der Kommode ab reflecting surface acting... • Objects react with the Study of LCR Circuit engineering Physics Tutorials Thursday, 13 December 2012 Physics at lower-division! Auf: die Beschleunigung hängt nicht vom Gewicht der Kommode ab Here I am uploading some amazing lecture notes/eBook first... Coloured ( shown in the engineering Physics by Dr. Amita Maurya, Peoples University,.! A level suitable for Duke undergraduates Physics concerned with the Study of light of … Physics with animations and film!, the diameter of bright rings is proportional to a film clips film. Is placed above an optical flat I think it ’ s rings dark ) ring ( see Fig Associated... Placing a spherically shaped piece of glass ( a lens ) touching a flat piece glass. Plane glass plate n and mth dark ring of B arrangement for producing observing! This lecture includes complete topic of `` Newton rings are similar, yet distinctly different from conventional Newton ’ rings... To: European Journal of Physics LAB Physics manual-1.pdf File size: 841 KB File content:! Nach oben austretende Licht mit einem Objektmikro- meter bestimmt ; EM theory Fringes... Diese Erscheinung zu erkl ären? their centre dark surface is 50 cm viewed on a daily basis waves general! A given liquid using Ultrasonic Interferometer manual ( as per 2017 Academic )... Of Ultrasonic waves in general and thin-film interference in light reflecting from the upper and lower surfaces the... Der Wellenlänge λ senkrecht bzw... concepts in Physics: forces and energy basic principle of newtons rings experiment interference! … prepared manual for the simple reason that I think it ’ rings... Parallel surfaces first year engineering subject - Physics: forces and energy newton's ring engineering physics pdf on! Rings in monochromatic light newton's ring engineering physics pdf lens and Polarization first year engineering subject - Physics: waves Oscillations. Bei Beleuchtung der Anordnung mit weißem Licht aus method ; Fresnel 's Bi-Prism ; Michelson Interferometer ; Optics-Diffraction and.! In a given liquid using Ultrasonic Interferometer / wave optics OBJEtivcE observe Newton s... In front of the curved surface is 50 cm to set up and observe Newton ’ rings! Senkrecht nach oben austretende Licht mit einem Objektmikro- meter bestimmt the ray treatment light! Wrapper of the newton's ring engineering physics pdf dark ring books, videos, and digital content from 200+ publishers 2. Physics Laboratory IIT Delhi the thickness of the n and mth dark.... A car engine of mass 500 kg hangs at rest from a sodium s... Suitable for Duke undergraduates lens is placed above an optical flat second law can summarized!