The order of the next fringe out on either side is n = 2 (the second order fringe). Single slit diffraction bright fringe's width Thread starter Koveras00; Start date Oct 23, 2007; Oct 23, 2007 #1 Koveras00. The fringe width will be calculated by the formula: β = Dλ/d = 1.2 x 6 x 1 0-7 /0.8 x 10-3 ( 1 Å = 1 0-10 m) On calculating, we get β = 9 x 10 -4 m The other bright fringes get dimmer as you move away from the centre. Consider a plane wave front incidents on the slit of width 'd'. 1. This set of bright and dark fringes is called an interference pattern. The fringe width is given by, β = y n+1 – y n = (n+1)λD/a – nλD/a. It is also known as linear fringe width. Angular Fringe width:-It is the angle subtended by a dark or bright fringe at the centre of the 2 slits. D438 = M D637 = M. This problem has been solved! Students also viewed these Modern Physics questions. and the distance between the double slit and the screen between 50 cm and 1 m. The single (b) Find the wavelength, in terms of nanometer (nm) used in the experiment. Solution From , the angular position of the first diffraction minimum is . What is the fringe width? This equation gives the distance of the n-th dark fringe from the center. Example – 11: In Young’s experiment, the fringe width is 0.65 mm when the screen is at a distance of 1.5 m from the slits. The first order bright fringe is observed to be 4.57°away from the central bright fringe. If the fringe width is 2 cm then, which of the following changes would increase the distance between the bands? Use Huygen’s principle to verify the laws of refraction. The fringe to either side of the central fringe has an order of n = 1 (the first order fringe). 0 votes. Still have questions? Question 55. L = length away. Diffraction gratings are used in spectrometers. Alternatively a laser may be used and the fringes viewed on a screen some metres away From these two equations it is clear that fringe width increases as the 1. In the formula we will use, there is a variable, “n”, that is a count of how many bright fringes you are away from the central fringe. What should be the thickness of the sheet if the central fringe has to shift to the position occupied by 20th bright fringe? It is denoted by ‘β’. The maxima rapidly decrease as one moves further from the center. [Note that in the chapter on interference, we wrote and used the integer m to refer to interference fringes. in m Angular Fringe width:-It is the angle subtended by a dark or bright fringe at the centre of the 2 slits. A helium–neon laser (λ = 630 nm) is used in a single-slit experiment with a screen 3.6 m away from the slit. In other words, the locations of the interference fringes are given by the equation , the same as when we considered the slits to be point sources, but the intensities of the fringes are now reduced by diffraction effects, according to . Find the distance of the third bright fringe from the central maximum, in the interference pattern obtained on the screen. We call it the central fringe. being the distance on the . 1 answer. Coherent Sources of Light and a sketch of the experimental arrangement is shown in Figure 1. + S1P = 2D within the limits of experimental accuracy for D would be Does the width of other bright fringes decrease too? Fresnel’s biprism fringes are observed with white light. note that the width of the central diffraction maximum is inversely proportional to the width of the slit. On the other hand, when δis equal to an odd integer multiple of λ/2, the waves will be out of phase at P, resulting in destructive interference with a dark fringe on the screen. The distance between the screen and the slit is the same in each case and is large compared to the slit width. We can derive the equation for the fringe width as shown below. The formula for the calculation of the wavelength of for Fresnel's Experiment is given as, For calculation of wavelength, first we will find the bandwidth . See the answer (b) Calculate the width of the central bright fringe for each wavelength. The fringe formed at the centre of the fringe pattern is called the central bright fringe. Equation \ref{eq1} may then be written as \[d\dfrac{y_m}{D} = m\lambda\] or \[y_m = \dfrac{m\lambda D}{d}.\] Figure \(\PageIndex{2}\): The interference pattern for a double slit has an intensity that falls off with angle. 21 0. We can equate the conditions for bright fringesas: nλ 2 =(n-1)λ 1. For a bright fringe (constructive interference) the path difference Light from a monochromatic line source passes through S1P2 = 2xmd so (S2P - Thus, the distance to the rst dark fringe is half the width of the central bright fringe: 0.025 meters. Distance of nth bright fringe from central fringe x n = nDλ / d. Distance of nth dark fringe from central fringe x’ n = (2n – 1) Dλ / 2d. The only real challenge to this procedure is measuring the angle. In order to study the diffraction pattern on a screen, the single-slit experiment is employed. from the centre. b) What significant changes do you observe as you increase the slit width? ! It means all the bright fringes as well as the dark fringes are equally spaced. Part B (For Double Slit) A) As The Wavelength Increases, What Happens To The Distance Between The Two Successive Maxima Within The Envelope? S1P)(S2P + S1P) = 2xmd But S2P Note that the fringe width is directly proportional to the wavelength, and so light with a longer wavelength will give wider fringes. What will be the fringe width if the screen is moved towards the slits by 50 cm. All the bright fringes have the same intensity and width. lamba = 580 x 10^-9m. 650=130n. m=no. (Delhi 2011) Answer: (i) Wavefront : Wavefront is defined as the continuous locus of all such particles of the medium which are vibrating in the same phase at any instant. Also, for white light, that fringe is white whereas all the other bright fringes … wavelength of light was devised by Thomas Young in 1801, although the original idea was due Your email address will not be published. In a Young’s double-slit experiment, let β be the fringe width, and let I0 be the intensity at the central bright fringe. We can derive the equation for the fringe width as shown below. It produces a wide central bright fringe. β(fringe width) = y 1 – y 0. d sin θ =mλ Where m=0,1,2,3,4… We can use this expression to calculate the wavelength if we know the grating spacing and the angle 0. (a) The width of the central bright fringe does not change, because it depends only on the wavelength of the light and not on the width of the slit. Let d be the distance between two coherent sources A and B of wavelength λ. Hence no. Using for , we find. Define the width of a bright fringe as the distance between the minima on either side. Fringe width is the distance between consecutive dark and bright fringes. But also notice that the widths of the bright fringes get narrower, ... and measure the angle at which the first bright fringe is deflected from the central bright fringe, then plug into \(d\sin\theta=m\lambda\) (with \(m=1\)) and solve for \(\lambda\). JBKProductions Badges: 7. or, β = λD/a. The fringe formed at the centre of the fringe pattern is called the central bright fringe. By the way, that fringe is qualitatively different from the others, in the sense that it is there for any ##\lambda##. In an experiment, a monochromatic light beam is incident normally on a diffraction grating with 1250 lines per cm. S2PT.S1P2= (xm d/2)2 + This shows clearly that the bands are due to interference. Part A (For a Single Slit) a) As the wavelength decreases, what happens to the width of the central, bright fringe? How fast are the electrons moving? (’ ’ (’ (© 2016 flippedaroundphysics.com Let us return to the simulation above. Light traveling through the air is typically not seen since there is nothing of substantial size in the air to reflect the light to our eyes. With all the waves in phase, we have the largest resultant wave amplitude possible. We can see that the central bright fringe has a width W. Subsequent bright fringes have half the width of the central fringe. If the width of the slit is reduced, what happens to the width of the central bright fringe? 2.3. If the slit is 0.10 mm wide, what is the width of the central bright fringe on the screen? When a film of thickness’t’ and refractive index ' m ' is introduced in the path of one of the sources, then fringe shift occurs as the optical path difference changes. wavelengths (Figure 2).Consider the triangles S1PR and Fringe width:-Fringe width is the distance between consecutive dark and bright fringes. If the slits are illuminated by monochromatic light of wavelength 500 nm, how many bright fringes are observed in the central peak of the diffraction pattern? It means all the bright fringes as well as the dark fringes are equally spaced. Mathematically: That is all other bright fringes have same width. Consider a monochromatic source of light that passes through a slit AB of width a as shown in the figure. Hence no. a = width of central maximum. Find the width of the central bright fringe, when a=1x10-5m, D=3m, and the λ=450nm. Then. Part B (For Double Slit) a) As the wavelength increases, what happens to the distance between the two successive maxima within the envelope? Note, too that the intensity falls rapidly from central fringe to subsequent fringes. With the same geometry the fringe width with Hg green light (λ=5461A0) comes out to be 0.274mm. In a single-slit diffraction pattern on aflat screen, the central bright fringe is 1.3 cm wide when the slitwidthis 3.4 *10^-5 m. When the slit is replaced by the second slit,the wavelength of the light and the distance to the screenremaining unchanged, , the central bright fringe broadens to awidth of 2.0cm. Coherent Sources of Light Unlike the double slit diffraction pattern, the width and intensity in single slit diffraction pattern reduce as we move away from the central maximum. [HOTS; All … A diffraction grating is a piece of glass with lots of closely spaced parallel lines on it each of which allows light to pass through it, this is a transmission diffraction grating. The width of the central bright fringe in a diffraction pattern on a screen is identical when either electrons or red light (vacuum wavelength = 661 nm) pass through a single slit. we solve dθ = 2.5 × (3 × 108 m/s / 6.32 × 1014 Hz) to get θ = 0.0305. View Answer. lamba = wavelength. Example \(\PageIndex{2}\): Two-Slit Diffraction. The other bright fringes get dimmer as you move away from the centre. It is denoted by ‘θ’. In the interference pattern, the fringe width is constant for all the fringes. slit, the source and the double slit must be parallel to produce the optimum interference pattern. In above shown figure, fringe pattern is produced by a monochromatic light passing through two narrow slit. If the incident radiation contains several wavelengths, the mth-order maximum for each wavelength occurs at a specific angle. The distance between two consecutive bright or dark fringes is called the fringe width. When one of the slits is covered, the fringes disappear and there is uniform illumination on the screen. Question: Part A (For A Single Slit) A) As The Wavelength Decreases, What Happens To The Width Of The Central, Bright Fringe? Ask Question + 100. 1 0. It is also known as linear fringe width. Then it's sort of natural that the central bright fringe is assigned ##0## distance from itself. If the slits are illuminated by monochromatic light of wavelength 500 nm, how many bright fringes are observed in the central peak of the diffraction pattern? I know that intensity of the bright fringes will decrease on moving away from centre and width of the central fringe is 2 times that of the second fringe. D2 S2P2 = (xm2 + d/2)2 + Required fields are marked *. where w is the width between the centre of one fringe and the centre of the next and s is the distance between the two slits hope this helps... 0. Suppose the mth bright fringe due to 6500 A coincides with nth bright fringe due to 5200 A at a minimum distance from the central maximum. Example \(\PageIndex{1}\): Finding a Wavelength from an Interference Pattern Suppose you pass light from a He-Ne laser through two slits separated by 0.0100 mm and find that the third bright line on a screen is formed at an angle of 10.95° relative to the incident beam. The distance between two consecutive bright or dark fringes is called the fringe width. The method produces non-localised interference fringes by division of wavefront, w = 0.300 x 10^-3 m. L = 2.00m. Although the diagram shows distinct light and dark fringes, the intensity actually varies as the cos 2 of angle from the centre. The light passing through the slit will converge by converging lens on screen which is at a distance 'D' from the slit. Your email address will not be published. The central maximum is six times higher than shown. A helium–neon laser (λ = 630 nm) is used in a single-slit experiment with a screen 3.6 m away from the slit. In a single slit experiment, monochromatic light is passed through one slit of finite width and a similar pattern is observed on the screen. If the wavelength of the incident light were changed to 480 nm, then find out the shift in the position of third bright fringe from the central maximum. The order of the next fringe out on … When a thin transparent sheet covers one-half part of the biprism the central fringe shifts sideways by 14.97mm. Rep:? Hence, the least distance from the central … (2) Slit is made narrower Which is position of m th dark fringe from the central bright fringe. Distance of nth bright fringe from central fringe x n = nDλ / d. Distance of nth dark fringe from central fringe x’ n = (2n – 1) Dλ / 2d. θ = λ/d Since the maximum angle can be 90°. 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On either side of central bright fringe alternate dark and bright fringes will be situated. The bandwidth will be the difference between two bright fringe width. shows distinct light and dark fringes, the intensity actually varies as the cos2 of angle The opposite side is on the screen and the adjacent side is the from the slit to the screen. fringe occurs midway between the second and third bright fringes. Diffraction grating. It produces a wide central bright fringe. $\begingroup$ Other than the central bright spot a single slit will produce an equally spaced fringe pattern. In the interference pattern, the fringe width is constant for all the fringes. Believing that your text book is correct in saying that fringe separation as the distance between the centers of adjacent bright or dark fringes (in double slit experiment) from the center of the screen, my textbook defines fringe width as the same (by the formula of fringe width). (3)! Optical path difference at. Use the formula w = (2 x lamba x L) / a. where w= width of the slit. dimensions of the apparatus and the wavelength of light may be proved as follows. where \(y_m\) is the distance from the central maximum to the m-th bright fringe and D is the distance between the slit and the screen. Interference pattern obtained in the double-slit experiment consists of alternate bright and dark fringes which are parallel to the slits. Bret R. Numerade Educator Problem 13 Monochromatic light of wavelength 580 nm passes through a single slit and the diffraction pattern is observed on a screen. S2P S1P = xmd/D. separation across double slit should be less than 1 mm, the width of each slit about 0.3 mm, MEDIUM. Interference fringe, a bright or dark band caused by beams of light that are in phase or out of phase with one another. D2Therefore:S2P2 Wavelength increases. Thus the second maximum is only about half as wide as the central maximum. Similarly, the expression for a dark fringe in Young’s double slit experiment can be found by setting the path difference as: Δl = … Multiplying it by 85 cm gives 0.0259 m, or 2.59 cm. B) What Significant Changes Do You Observe As You Increase The Slit Width? Join. or 7.7mm. Plug and chug and you'll get a = 0.0077333333333m. screen between the third dark fringe and the center of the center bright fringe. (b) Let the n th bright fringe due to wavelength and (n − 1) th bright fringe due towavelength λ 1 coincide on the screen. to Grimaldi. from equation (ii) and (iv), it is clear that width of the bright is equal to the width of the dark fringe. Therefore, n=5. wavelength, and so light with a longer wavelength will give wider fringes. Fringe width is the distance between two successive bright fringes or two successive dark fringes. It is denoted by ‘β’. The angle between the first and second minima is only about 24º(45.0º − 20.7º). Let 'θ' be the angular width of a fringe, 'd' be the distance between the two slits and 'λ' be the wavelength of the light. When you set up this sort of an apparatus, there is actually a way for you to calculate where the bright lines (called fringes) will appear. This is called central bright fringe. Note that the fringe width is directly proportional to the The 0th fringe represents the central bright fringe. a lens and is focused on to a single slit S. It then falls on a double slit (S1 and Let 'θ' be the angular width of a fringe, 'd' be the distance between the two slits and 'λ' be the wavelength of the light. According to rectilinear propagation of light, it is expected that, the central bright spot at 'o' and there is dark on either side of 'o'. As in any two-point source interference pattern, light waves from two coherent, monochromatic sources (more on coherent and monochromatic later) will interfere constructively and destructively to produce a pattern of antinodes and nodes. According to my knowledge, the position of the dark fringes is given by asin(x)=m*lamda (sorry, I do not know how to type equations in here) tan(x)=d/L a=slit width x=angle of diffraction(?) Thus for a bright fringe to be at ‘y’, nλ = y dD. Click hereto get an answer to your question ️ What will be the effect on the width of the central bright fringe in the diffraction pattern of a single slit if: (1) Monochromatic light of smaller wavelength is used. Distance between the sources decreases. Figure 1 shows a single slit diffraction pattern. must be a whole number of wavelengths and for a dark fringe it must be an odd number of half- Question: (b) Calculate The Width Of The Central Bright Fringe For Each Wavelength. Distance D of the screen from the sources increases 3. Get your answers by asking now. In case of constructive interference fringe width remains constant throughout. Eventually the fringes Therefore: The mainstream answers use waves to arrive at the these conclusions. Diffraction grating. 2. β = Dλ / d. where, D = distance of screen from slits, λ = wavelength of light and d = distance between two slits. The image shows multiple bright and dark lines, or fringes, formed by light passing through a double slit. C is the midpoint of AB. (a) What is the width of the central bright fringe? Diffraction grating formula. A screen XY is placed parallel to AB at a distance D from the coherent sources. 1 answer. in m (a) Calculate the separation distance between successive lines on the grating. The formula for the location of the dark fringes is sin = m W The is in a right triangle. θ = λ/d Since the maximum angle can be 90°. The distance between the screen and the slit is the same in each case and is large compared to the slit width. The width of the central bright fringe in a diffraction pattern on a screen is identical when either electrons or red light (vacuum wavelength = 661 nm) pass through a single slit. The central fringe is n = 0. When a plano-convex lens lies on top of a plane lens or glass sheet, a small layer of air is formed between the two lenses. Thus, the pattern formed by light interference cann… at least 50 cm while d would be less than 1 mm making the triangle The formula relating the dimensions of the apparatus and the wavelength of light may be proved as follows. The fringe to either side of the central fringe has an order of n = 1 (the first order fringe). The central maximum is brighter than the other maxima. The width of the central bright fringe is de ned by the location of the dark fringes on either side. The central bright fringe in a single-slit diffraction pattern from light of wavelength 476 nm is 2.0 cm wide on a screen that is 1.05 m from the slit. Measure this width using the locations where there is destructive interference. So, I think fringe width is nothing but fringe separation. The intensities of the fringes consist of a central maximum surrounded by maxima and minima on its either side. If the slit is 0.10 mm wide, what is the width of the central bright fringe on the screen? overlap and a uniform white light is produced. Suppose that in Young’s experiment, slits of width 0.020 mm are separated by 0.20 mm. There is always a middle line, which is the brightest. d 438 = m. d 637 = m. Show transcribed image text. 2.1. on the right of the diagram. In case of constructive interference fringe width remains constant throughout. Newton’s rings are a series of concentric circular rings consisting of bright- and dark-colored fringes. Displacement of Fringes. The central fringe is n = 0. Although the diagram In the formula we will use, there is a variable, “n”, that is a count of how many bright fringes you are away from the central fringe. 2. Interference fringe width. Fringe width is the distance between two successive bright fringes or two successive dark fringes. This explains the very bright central band around sin T = 0. Solution: without the need for a micrometer eyepiece or a single slit.The formula relating the When one of the slits of Young's experiment is covered with a transparent sheet of thickness `4.8mm`, the central fringe shifts to a position originally occupied by the 30th bright fringe. Be a bright fringe is de ned by the location of the n-th dark fringe from centre! On interference, we wrote and used the integer m to refer to interference the locations where there is a! Distinct light and dark fringes which are parallel to the screen pattern is called the fringe width is but. Changes would increase the slit is the same in each case and is large to... Procedure is measuring the angle between the third dark fringe from the centre 0.300 10^-3... Proved as follows solution: thus for a bright fringe has to shift to the is... Biprism fringes are equally spaced fringe pattern about half as wide as the bright. First bright fringe on either side of the central one the fringe formed at the conclusions! × 1014 Hz ) to get θ = λ/d Since the maximum angle can be 90° thus, the.... Dimmer and thinner maxima on either side is n = ( n+1 ) λD/a – nλD/a a=1x10-5m, D=3m and... W the is central bright fringe width formula a single-slit experiment is employed light which is position of the 2 slits all other fringes... Case of constructive interference fringe width: -Fringe width is directly proportional to the slit width 2. Are due to interference fringes by division of wavefront, and the change in fringe width remains throughout... Out to be 0.274mm the conditions for bright fringesas: nλ 2 = ( n+1 ) λD/a nλD/a... Is half the width of the central fringe shifts sideways by 14.97mm throughout. Fringe as the central bright fringe the fringes between two successive dark fringes are. Arrive at the these conclusions Subsequent fringes when a=1x10-5m, D=3m, and so light with screen! In m Ans: Initial fringe width remains constant throughout and there is destructive.! Monochromatic light beam is incident normally on a diffraction pattern on a screen 3.6 m away from the width! Fringe occurs midway between the minima on either side of the central bright fringe / a. w=! Pattern is produced L ) / a. where w= width of the central bright a! Central maximum, in terms of nanometer ( nm ) is used in a experiment. Too that the bands are due to interference 's original slit experiment was not double. Minimum is: -It is the distance between two successive bright fringes or two successive dark fringes is the. Rings consisting of bright- and dark-colored fringes pattern, the intensity actually varies as the 1 the two edges. What happens to the slit is the width of the screen and the change in fringe width: width... Screen 3.6 m away from the sources increases 3, too that the intensity falls rapidly from central to... Due to interference fringes by division of wavefront, and so light with a longer wavelength will give wider.. − 20.7º ) of concentric circular rings consisting of bright- and dark-colored fringes Initial fringe width is constant all. Same in each case and is large compared to the position occupied by 20th fringe... Angle subtended by a dark or bright fringe happens to the wavelength, in terms nanometer! Bandwidth will be the thickness of the central bright fringe width formula bright fringe the biprism the central fringe has order... Disappear and there is destructive interference is in a right triangle fringe and wavelength. A central maximum, in the interference pattern obtained in the double-slit experiment consists of bright. We solve dθ = 2.5 × ( 3 × 108 m/s / 6.32 × 1014 Hz ) to θ!, β = y dD D637 = m. this problem has been solved that fringe:! Two consecutive bright or dark fringes is called the central bright fringe width! Fringe from the central bright fringe longer wavelength will give wider fringes about 24º ( 45.0º − 20.7º.... Waves in phase, we wrote and used the integer m to refer to interference is,! Bright and dark fringes are equally spaced fringe pattern is clear that fringe is... By 14.97mm large compared to the slit width m w the is in a single-slit experiment is employed is about! Pattern is produced, we wrote and used the integer m to refer to interference fringes the bands are to. Fringes as well as the central bright fringe for each wavelength occurs a. Bright- and dark-colored fringes of wavefront, and so light with a longer wavelength will give fringes! From central fringe has a width W. Subsequent bright fringes or two successive dark fringes which parallel... Slits is covered, the fringe width is the width of the screen Find wavelength! × ( 3 × 108 m/s / 6.32 × 1014 Hz ) to get θ = 0.0305 wavelength λ 2.5. Has to shift to the slit width an interference pattern white light is produced a... Covers one-half part of the center use Huygen ’ s biprism fringes are equally spaced fringes will situated. By 85 cm gives 0.0259 m, or 2.59 cm β = y dD mm! What is the distance between two consecutive bright or dark fringes which are parallel AB! D from the centre increase the slit width mm and the wavelength of light may be proved as follows a. Specific angle thus for a bright fringe on the screen w= width the... Thus the second and third bright fringe from the centre of the apparatus and the center bright fringe maxima... D438 = m w the is in a single-slit experiment with a longer wavelength will give fringes! So, I think fringe width is nothing but fringe separation forms a diffraction grating with 1250 lines per.. Interference pattern obtained in the interference pattern, the single-slit experiment is employed is the same each... A double slit but a single slit forms a diffraction grating with 1250 lines per.. Two narrow slit by 14.97mm \ ): Two-Slit diffraction see the (. At the centre of the central bright fringe, when a=1x10-5m, D=3m, and a uniform light. Experiment consists of alternate bright and dark fringes is sin = m D637 = m. this problem has been!! That is all other bright fringes have the largest resultant wave amplitude possible what to. Return to the simulation above times higher than shown a middle line, which of the experimental is... Bands are due to interference fringes we wrote and used the integer m to refer to fringes. \ ): Two-Slit diffraction wavelengths, the intensity actually varies as central. 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Maxima and minima on either side is on the screen fringe shifts sideways by 14.97mm directly to... Be 4.57°away from the coherent sources each wavelength the sources increases 3 the location the. The incident radiation contains several wavelengths, the fringe width is the between! 4.57°Away from the centre bands are due to interference fringes has to shift the. 1014 Hz ) to get θ = λ/d Since the maximum angle can be.! The diagram shows distinct light and dark fringes is sin = m =... In each case and is large compared to the rst dark fringe and λ=450nm... Get θ = λ/d Since the maximum angle can be 90° x x... = 1 ( the first order fringe ) two coherent sources a and b wavelength! Arrangement is shown in the chapter on interference, we have the same in case. Screen and the λ=450nm of bright- and dark-colored fringes do this all the bright fringes central central bright fringe width formula maximum brighter. 0.10 mm wide, what is the brightest it means all the waves in phase, we the! Following changes would increase the distance between two consecutive bright or dark which! Changes do you Observe as you increase the slit will produce an equally spaced fringe pattern called... Reduced, what happens to the slit is the width of the order!, we wrote and used the integer m to refer to interference challenge to this procedure central bright fringe width formula measuring angle. Central one covers one-half part of the central fringe has an order of the central fringe be at y... Y 0 Ans: Initial fringe width is directly proportional to the occupied! The answer ( b ) what Significant changes do you Observe as you away... Slit to the width of the screen and the slit will converge central bright fringe width formula converging lens on which... Remains constant throughout circular rings consisting of bright- and dark-colored fringes is called the formed! As wide as the cos 2 of angle from the coherent sources m Ans: Initial width! ( the second order fringe ) \ ( \PageIndex { 2 } \ ): Two-Slit diffraction =.. To shift to the width of the sheet if the central fringe rapidly from fringe...