As shown in the figure, a ray of unpolarized light enters from water of refractive index into a medium of refractive index after passing through a glass plate of refractive index and a layer of water. At a particular incident angle the reflected ray is polarized in the direction as shown in the figure. The value of (in degrees) is:
Wave Optics — JEE Previous Year Questions
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In the List-I, four optical effects are mentioned. The physical phenomena of light which are essential to describe these optical effects are given in List-II. Choose the option which describes the correct match between the entries in List-I to those in List-II.
| List-I | List-II |
|---|---|
| P.Colorful sky in north polar region (Aurora Borealis) | 1.Dispersion and reflection |
| Q.Partially polarized sun light | 2.Total internal reflection |
| R.Rainbow | 3.Diffraction |
| S.Dark and bright fringes | 4.Scattering of light by molecules in the atmosphere |
| 5.Emission of radiation from oxygen and nitrogen atoms excited by charged particles |
- (A)P→5, Q→4, R→1, S→3
- (B)P→4, Q→2, R→1, S→3
- (C)P→4, Q→1, R→2, S→3
- (D)P→5, Q→4, R→1, S→2
Some distant star is to be observed by some telescope of diameter of objective lens , at an angular resolution of radian. If the wavelength of light from the star reaching the telescope is 500 nm, the minimum diameter of the objective lens of the telescope is ________ cm. (nearest integer)
An unpolarized light of intensity passes through polarizer and then through a certain optically active solution and finally it goes to analyser. If the angle between analyser and polariser is 0° and intensity of light emerged from analyser is , the angle of rotation of the light by the solution with respect to analyser is _______ degrees.
In a Young double slit experiment, the wavelength of incident light is 6000 Å, the separation between slits and is 5 cm and the distance between slits plane and screen is 50 cm, as shown in the figure below. If the resultant intensity at is equal to the intensity due to individual slits, the path difference between interfering waves is __________ Å.
- (A)4000
- (B)3000
- (C)2000
- (D)1000
In interference experiment the path difference between two interfering waves at a point A on the screen is λ/3, where λ is the wavelength of these waves, and at another point B the path difference is λ/6. The ratio of intensities at points A and B is ________.
- (A)3
- (B)4
- (C)1/3
- (D)1/4
The maximum intensity in a Young's double slit experiment is . Distance between the slits () is 5λ, where λ is the wavelength of light used. The intensity of the fringe, exactly opposite to one of the slits on the screen, placed at is ________.
- (A)
- (B)
- (C)
- (D)
In Young's double slit experiment, the fringe width of the interference pattern produced on the screen is 2.4 μm. If the experiment is carried out in another medium having refractive index 1.2, the fringe width will be _____ μm.
- (A)1.2
- (B)2
- (C)2.4
- (D)2.88
An unpolarized light of certain intensity passes through a combination of two polarizers whose transmission axes are at 30° and 90°, respectively, with respect to the horizontal axis. A third polarizer with its transmission axis at 60° with the horizontal axis is placed between the two existing polarizers. The ratio of the output intensities with and without the third polarizer is ______.
- (A)3/4
- (B)4/3
- (C)9/4
- (D)4/9
In a double slit experiment, when one of the slits is covered by a transparent mica sheet of refractive index 1.56, the central fringe shifts to the position of bright fringe, obtained with both slits uncovered. If the light source wavelength is 450 nm, the thickness of mica sheet is α × m. The value of α is ______.
A slit of width is illuminated by light of wavelength . The linear separation between and minima in the diffraction pattern produced on a screen placed at a distance from the slit system is _____.
- (A)
- (B)
- (C)
- (D)
An unpolarized light is incident on the plane interface of air-dielectric medium shown in figure. If the incident angle is equal to Brewster angle, identify the expression representing reflected wave.
- (A)
- (B)
- (C)
- (D)
A telescope with objective diameter is used to observe a distant star emitting light of wavelength 500 nm, at a resolution of radian. The value of is ______ cm.
- (A)61
- (B)122
- (C)244
- (D)305
In single slit diffraction pattern, the wavelength of light used is 628 nm and slit width is 0.2 mm, the angular width of central maximum is degrees. The value of α is ________.
In a Young's double slit experiment, the intensity at some point on the screen is found to be times of the maximum of the interference pattern. The path difference between the interfering waves at this point is where is wavelength of the incident light. The value of is ________.
Given below are two statements :
Statement-I : A plane wave after passing through prism remains as plane wave but passing through small pin hole may become spherical wave.
Statement-II : The curvature of a spherical wave emerging from a slit will increase for increasing slit width.
In the light of the above statements, choose the correct answer from the options given below.
- (A)Both Statement-I and Statement-II are false.
- (B)Both Statement-I and Statement-II are true.
- (C)Statement-I is true but Statement-II is false.
- (D)Statement-I is false but Statement-II is true.
A beam of light consisting of wavelengths 650 nm and 550 nm illuminates the Young's double slits with separation of 2 mm such that the interference fringes are formed on a screen, placed at a distance of 1.2 m from the slits. The least distance of a point from the central maximum, where the bright fringes due to both the wavelengths coincide, is _______ m.
In the Young's double slit experiment the intensity produced by each one of the individual slits is . The distance between two slits is 2 mm. The distance of screen from slits is 10 m. The wavelength of light is 6000 . The intensity of light on the screen in front of one of the slits is _____.
- (A)
- (B)
- (C)
- (D)
An unpolarised light is incident at an interface of two dielectric media having refractive indices of 2 (incident medium) and (medium) respectively. To satisfy the condition that reflected and refracted rays are perpendicular to each other, the angle of incidence is ______.
- (A)60°
- (B)10°
- (C)30°
- (D)45°
When an unpolarized light falls at a particular angle on a glass plate (placed in air), it is observed that the reflected beam is linearly polarized. The angle of refracted beam with respect to the normal is ________.
( (1.52) = 57.7°, refractive indices of air and glass are 1.00 and 1.52, respectively)
- (A)39.6°
- (B)32.3°
- (C)42.6°
- (D)36.3°
In two separate Young's double-slit experimental set-ups, two monochromatic light sources of different wavelengths are used to get fringes of equal width. The ratios of the slit separations and that of the wavelengths of light used are 2 : 1 and 1 : 2 respectively. The corresponding ratio of the distances between the slits and the respective screens () is ______.
The wavelength of light, while it is passing through water is 540 nm. The refractive index of water is . The wavelength of the same light when it is passing through a transparent medium having refractive index of is _________nm.
- (A)380
- (B)840
- (C)480
- (D)540
Given below are two statements:
Statement I : In a Young's double slit experiment, the angular separation of fringes will increase as the screen is moved away from the plane of the slits
Statement II : In a Young's double slit experiment, the angular separation of fringes will increase when monochromatic source is replaced by another monochromatic source of higher wavelength
In the light of the above statements, choose the correct answer from the options given below:
- (A)Both Statement I and Statement II are true
- (B)Both Statement I and Statement II are false
- (C)Statement I is false but Statement II is true
- (D)Statement I is true but Statement II is false
In a double slit experiment the distance between the slits is 0.1 cm and the screen is placed at 50 cm from the slits plane. When one slit is covered with a transparent sheet having thickness t and refractive index n(= 1.5), the central fringe shifts by 0.2 cm. The value of t is _____ cm.
- (A)
- (B)
- (C)
- (D)
In a Young's double slit experiment set up, the two slits are kept 0.4. mm apart and screen is placed at 1 m from slits. If a thin transparent sheet of thickness 20 μm is introduced in front of one of the slits then centre bring fringe shifts by 20 mm on the screen. The refractive index of transparent sheet is given by , where is ________.
In a Young's double slit experiment, a combination of two glass wedges A and B, having refractive indices 1.7 and 1.5, respectively, are placed in front of the slits, as shown in the figure. The separation between the slits is d = 2mm and the shortest distance between the slits and the screen is D = 2m. Thickness of the combination of the wedges is t = 12 μm. The value of as shown in the figure is 1 mm. Neglect any refraction effect at the slanted interface of the wedges. Due to the combination of the wedges, the central maximum shifts (in mm) with respect to O by ______
In a Young’s double slit experiment, the source is white light. One of the slits is covered by red filter and another by a green filter. In this case (1) There shall be an interference pattern for red distinct from that for green. (2) There shall be no interference fringes. (3) There shall be alternate interference fringes of red and greens. (4) There shall be an interference pattern, where each fringe’s pattern center is green and outer edges is red.
- (A)There shall be an interference pattern for red distinct from that for green.
- (B)There shall be no interference fringes.
- (C)There shall be alternate interference fringes of red and greens.
- (D)There shall be an interference pattern, where each fringe’s pattern center is green and outer edges is red.
In a Young's double slit experiment, the slits are separated by 0.2 mm. If the slits separation is increased to 0.4 mm, the percentage change of the fringe width is:
- (A)0%
- (B)100%
- (C)50%
- (D)25%
In a Young's double slit experiment, two slits are located 1.5 mm apart. The distance of screen from slits is 2 m and the wavelength of the source is 400 nm. If the double slit pattern is replaced with a single slit of width equal to that of each slit, then the width of 20 maxima of double slit is ______ times the width of central maxima of single slit. (take x-value is ______)
Two polarisers and are placed in such a way that the intensity of the transmitted light will be zero. A third polariser is inserted in between and at the particular angle between them. The transmitted intensity of the light passing through all three polarisers is maximum. The angle between the polarisers and is:
- (A)
- (B)
- (C)
- (D)
Two coherent monochromatic light beams of intensities and are superimposed. The difference between the maximum and minimum intensities in the resulting interference pattern is . The value of is __________.
Two monochromatic light beams have intensities in the ratio 1:9. An interference pattern is obtained by these beams. The ratio of the intensities of maximum to minimum is:
- (A)
- (B)
- (C)
- (D)
Width of one of the two slits in a Young's double slit interference experiment is half of the other slit. The ratio of the maximum to the minimum intensity in the interference pattern is:
- (A)
- (B)
- (C)
- (D)
If the measured angular separation between the second minimum to the left of the central maximum and the third minimum to the right of the central maximum is in a single slit diffraction pattern recorded using 628 nm light, then the width of the slit is ______ m.
A light wave is propagating with plane wave fronts of the type constant. The angle made by the direction of wave propagation with the x-axis is:
- (A)
- (B)
- (C)
- (D)
A double slit interference experiment performed with a light of wavelength 600 nm forms an interference fringe pattern on a screen with bright fringe having its centre at a distance of 10 mm from the central maximum. Distance of the centre of the same bright fringe from the central maximum when the source of light is replaced by another source of wavelength 660 nm would be_____mm.
In a Young's double slit experiment, three polarizers are kept as shown in the figure. The transmission axes of and are orthogonal to each other. The polarizer covers both the slits with its transmission axis at to those of and . An unpolarized light of wavelength and intensity is incident on and . The intensity at a point after where the path difference between the light waves from and is , is
- (A)
- (B)
- (C)
- (D)
The Young’s double slit interference experiment is performed using light consisting of 480 nm and 600 nm wavelengths to form interference fringes. The least number of the bright fringes of 480 nm light that are required for the first coincidence with the bright fringes formed by 600 nm light is :-
- (A)4
- (B)8
- (C)6
- (D)5
Young's double slit interference apparatus is immersed in a liquid of refractive index 1.44. It has slit separation of 1.5 mm. The slits are illuminated by a parallel beam of light whose wavelength in air is 690 nm. The fringe-width recorded behind the plane of slits at a distance of 0.72 m, will be :
- (A)0.23 mm
- (B)0.33 mm
- (C)0.63 mm
- (D)0.46 mm
The width of one of the two slits in Young's double slit experiment is while that of the other slit is . If the ratio of the maximum to the minimum intensity in the interference pattern on the screen is what is the value of ? (Assume that the field strength varies according to the slit width.)
- (A)
- (B)
- (C)
- (D)
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): In Young's double slit experiment, the fringes produced by red light are closer as compared to those produced by blue light.
Reason (R): The fringe width is directly proportional to the wavelength of light. In the light of above statements, choose the correct answer from the options given below:
- (A)Both (A) and (R) are true and (R) is the correct explanation of (A)
- (B)(A) is false but (R) is true
- (C)Both (A) and (R) are true but (R) is NOT the correct explanation of (A)
- (D)(A) is true but (R) is false
Assertion (A): If Young’s double-slit experiment is performed in an optically denser medium than air, the consecutive fringes come closer.
Reason (R): The speed of light reduces in an optically denser medium than air, while its frequency does not change.
In the light of the above statements, choose the most appropriate answer:
- (A)Both (A) and (R) are true and (R) is the correct explanation of (A)
- (B)(A) is false but (R) is true
- (C)Both (A) and (R) are true but (R) is not the correct explanation of (A)
- (D)(A) is true but (R) is false
In a Young's double slit experiment, each of the two slits A and B, as shown in the figure, are oscillating about their fixed center and with a mean separation of 0.8 mm. The distance between the slits at time is given by mm, where rad s. The distance of the screen from the slits is 1 m and the wavelength of the light used to illuminate the slits is 6000 Å. The interference pattern on the screen changes with time, while the central bright fringe (zeroth fringe) remains fixed at point O.
The bright fringe above the point O oscillates with time between two extreme positions. The separation between these two extreme positions, in micrometer (μm), is
In a Young's double slit experiment, each of the two slits A and B, as shown in the figure, are oscillating about their fixed center and with a mean separation of 0.8 mm. The distance between the slits at time is given by mm, where rad s. The distance of the screen from the slits is 1 m and the wavelength of the light used to illuminate the slits is 6000 Å. The interference pattern on the screen changes with time, while the central bright fringe (zeroth fringe) remains fixed at point O.
The maximum speed in μm/s at which the bright fringe will move is
A point source emits unpolarized light uniformly in all directions. At two points and , the ratio of the intensities of light is 2. If a set of two polaroids having angle between their pass-axes is placed just before point , then the new value of will be ______.
Monochromatic light of wavelength 500 nm is used in Young's double slit experiment. An interference pattern is obtained on a screen. When one of the slits is covered with a very thin glass plate (refractive index = 1.5), the central maximum is shifted to a position previously occupied by the bright fringe. The thickness of the glass plate is _______ m.
In a Young's double slit experiment, the intensity at a point is of the maximum intensity, the minimum distance of the point from the central maximum is ______ m. (Given: nm, mm, m)
A parallel beam of monochromatic light of wavelength passes through single slit of width. Angular divergence corresponding to second order minima would be ___ rad.
Two slits are 1 mm apart and the screen is located 1 m away from the slits. A light of wavelength 500 nm is used. The width of each slit to obtain 10 maxima of the double slit pattern within the central maximum of the single slit pattern is ________ m.
Two coherent monochromatic light beams of intensities and are superimposed. The difference between maximum and minimum possible intensities in the resulting beam is . The value of x is ______ .
In a single slit experiment, a parallel beam of green light of wavelength 550 nm passes through a slit of width 0.20 mm. The transmitted light is collected on a screen 100 cm away. The distance of the first order minima from the central maximum will be m. The value of is __________.
In Young’s double slit experiment, carried out with light of wavelength , the distance between the slits is 0.3 mm and the screen is at 200 cm from the slits. The central maximum is at cm. The value of for the third maximum is ___ mm.
Light emerges out of a convex lens when a source of light is kept at its focus. The shape of wavefront of the light is:
- (A)Both spherical and cylindrical
- (B)Cylindrical
- (C)Spherical
- (D)Plane
The width of one of the two slits in a Young's double slit experiment is 4 times that of the other slit. The ratio of the maximum to the minimum intensity in the interference pattern is
- (A)
- (B)
- (C)
- (D)
Two wavelengths and are used in Young's double slit experiment. and . The minimum order of fringe produced by which overlaps with the fringe produced by is . The value of is ___
In Young's double slit experiment, monochromatic light of wavelength 5000 \AA{} is used. The slits are 1.0 mm apart and screen is placed at 1.0 m away from slits. The distance from the centre of the screen where intensity becomes half of the maximum intensity for the first time is __________ m.
A microwave of wavelength 2.0 cm falls normally on a slit of width 4.0 cm. The angular spread of the central maxima of the diffraction pattern obtained on a screen 1.5 m away from the slit, will be:
- (A)
- (B)
- (C)
- (D)
Two waves of intensity ratio 1 : 9 cross each other at a point. The resultant intensities at the point, when (a) Waves are incoherent is (b) Waves are coherent and differ in phase by is . If then ______.
A beam of unpolarised light of intensity is passed through a polaroid A and then through another polaroid B which is oriented so that its principal plane makes an angle of relative to that of A. The intensity of emergent light is:
- (A)
- (B)
- (C)
- (D)
In a double slit experiment shown in figure, when light of wavelength 400 nm is used, dark fringe is observed at P. If m the minimum distance between the slits and is ______ mm.
In a single slit diffraction pattern, a light of wavelength 6000 Å is used. The distance between the first and third minima in the diffraction pattern is found to be 3 mm when the screen is placed 50 cm away from slits. The width of the slit is ___ m.
In Young's double slit experiment, light from two identical sources are superimposing on a screen. The path difference between the two lights reaching at a point on the screen is . The ratio of intensity of fringe at this point with respect to the maximum intensity of the fringe is:
- (A)
- (B)
- (C)
- (D)
When a polaroid sheet is rotated between two crossed polaroids then the transmitted light intensity will be maximum for a rotation of :
- (A)
- (B)
- (C)
- (D)
A single slit of width is illuminated by a monochromatic light of wavelength nm. The value of 'a' for which first minimum appears at on the screen will be :
- (A)m
- (B)m
- (C)m
- (D)m
In a Young's double slit experiment, the ratio of amplitude of light coming from slits is 2:1. The ratio of the maximum to minimum intensity in the interference pattern is:
- (A)9 : 4
- (B)9 : 1
- (C)2 : 1
- (D)25 : 9
The ratio of intensities at two points P and Q on the screen in a Young's double slit experiment, where the phase differences between the two waves of same amplitude are and respectively, is:
- (A)
- (B)
- (C)
- (D)
Unpolarised light of intensity passes through the combination of three polaroids such that the pass axis of the last polaroid is perpendicular to that of the pass axis of first polaroid. If intensity of emerging light is , then the angle between pass axis of first two polaroids is _________ °.
The width of a fringe is 2 mm on the screen in a double slit experiment for light of wavelength 400 nm. The width of the fringe for light of wavelength 600 nm will be:
- (A)4 mm
- (B)1.33 mm
- (C)3 mm
- (D)2 mm
Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: The phase difference of two light waves change if they travel through different media having same thickness, but different indices of refraction.
Reason R: The wavelengths of waves are different in different media.
In the light of the above statements, choose the most appropriate answer from the options given below
- (A)Both A and R are correct but R is NOT the correct explanation of A
- (B)A is correct but R is not correct
- (C)Both A and R are correct and R is the correct explanation of A
- (D)A is not correct but R is correct
A beam of light consisting of two wavelengths 7000 Å and 5500 Å is used to obtain interference pattern in Young's double slit experiment. The distance between the slits is 2.5 mm and the distance between the plane of slits and the screen is 150 cm. The least distance from the central fringe, where the bright fringes coincide, will be m. The value of is
'' polarizing sheets are arranged such that each makes an angle with the preceeding sheet. An unpolarized light of intensity is incident into this arrangement. The output intensity is found to be . The value of will be:
- (A)
- (B)
- (C)
- (D)
In Young's double slit experiment, a thin plate of thickness and refractive index is inserted in front of slit . The experiment is conducted in air () and uses a monochromatic light of wavelength nm. Due to the insertion of the plate, central maxima is shifted by a distance of . is the fringe-width before the insertion of the plate. The value of the is _________.
Two light waves of wavelengths and nm are used in Young's double slit experiment to obtain interference fringes on a screen placed m away from plane of slits. If the two slits are separated by mm, then shortest distance from the central bright maximum to the point where the bright fringes of the two wavelength coincide will be _________ mm.
Two polaroids and are placed in such a way that the pass-axis of polaroids are perpendicular to each other. Now, another polaroid is placed between and bisecting angle between them. If intensity of unpolarized light is then intensity of transmitted light after passing through polaroid will be:
- (A)
- (B)
- (C)Zero
- (D)
In Young's double slit experiment, two slits and are '' distance apart and the separation from slits to screen is D (as shown in figure). Now if two transparent slabs of equal thickness mm but refractive index and are introduced in the path of beam ( Å) from and respectively. The central bright fringe spot will shift by _________ number of fringes.
In a Young's double slit experiment, the intensities at two points, for the path differences and ( being the wavelength of light used) are and respectively. If denotes the intensity produced by each one of the individual slits, then _______.
In a Young's double slit experiment, two slits are illuminated with a light of wavelength 800 nm. The line joining is perpendicular to as shown in the figure. If the first minimum is detected at , the value of slits separation '' will be: (The distance of screen from slits cm)
- (A)0.5 mm
- (B)0.1 mm
- (C)0.4 mm
- (D)0.2 mm
As shown in the figure, three identical polaroids , and are placed one after another. The pass axis of and are inclined at angle of and with respect to the axis of . The source has an intensity of . The intensity of light at point is ________ .
A scientist is observing a bacteria through a compound microscope. For better analysis and to improve its resolving power he should. (Select the best option)
- (A)Increase the refractive index of the medium between the object and objective lens
- (B)Decrease the diameter of the objective lens
- (C)Decrease the wave length of the light
- (D)Decrease the focal length of the eye piece
In Young's double slit experiment, the position of the bright fringe from the central maximum is 5 cm. The distance between slits and screen is 1 m and wavelength of used monochromatic light is 600 nm. The separation between the slits is:
- (A)
- (B)
- (C)
- (D)
Given below are two statements:
Statement I: If the Brewster's angle for the light propagating from air to glass is , then the Brewster's angle for the light propagating from glass to air is .
Statement II: The Brewster's angle for the light propagating from glass to air is where is the refractive index of glass.
In the light of the above statements, choose the correct answer from the options given below:
- (A)Both Statement I and Statement II are false
- (B)Statement I is true but Statement II is false
- (C)Statement I is false but Statement II is true
- (D)Both Statement I and Statement II are true
A double slit setup is shown in the figure. One of the slits is in medium 2 of refractive index . The other slit is at the interface of this medium with another medium 1 of refractive index . The line joining the slits is perpendicular to the interface and the distance between the slits is d . The slit widths are much smaller than d . A monochromatic parallel beam of light is incident on the slits from medium 1. A detector is placed in medium 2 at a large distance from the slits, and at an angle from the line joining them, so that equals the angle of refraction of the beam. Consider two approximately parallel rays from the slits received by the detector.
Which of the following statement(s) is(are) correct?
- (A)The phase difference between the two rays is independent of d .
- (B)The two rays interfere constructively at the detector.
- (C)The phase difference between the two rays depends on but is independent of .
- (D)The phase difference between the two rays vanishes only for certain values of d and the angle of incidence of the beam, with being the corresponding angle of refraction.
An unpolarised light beam of intensity is passed through a polaroid P and then through another polaroid Q which is oriented in such a way that its passing axis makes an angle of 30° relative to that of P. The intensity of the emergent light is
- (A)
- (B)
- (C)
- (D)
Two light beams of intensities 4I and 9I interfere on a screen. The phase difference between these beams on the screen at point A is zero and at point B is . The difference of resultant intensities, at the point A and B, will be __________ I.
In a Young's double slit experiment, a laser light of 560 nm produces an interference pattern with consecutive bright fringes' separation of 7.2 mm. Now another light is used to produce an interference pattern with consecutive bright fringes' separation of 8.1 mm. The wavelength of second light is ________ nm.
Two beams of light having intensities I and 4I interfere to produce a fringe pattern on a screen. The phase difference between the two beams are and at points A and B respectively. The difference between the resultant intensities at the two points is xI. The value of x will be ______ .
Two coherent sources of light interfere. The intensity ratio of two sources is 1 : 4. For this interference pattern if the value of is equal to , then will be :
- (A)1.5
- (B)2
- (C)0.5
- (D)1
In young's double slit experiment, the fringe width is 12mm. If the entire arrangement is placed in water of refractive index , then the fringe width becomes (in mm)
- (A)16
- (B)9
- (C)48
- (D)12
In a double slit experiment with monochromatic light, fringes are obtained on a screen placed at some distance from the plane of slits. If the screen is moved by m towards the slits, the change in fringe width is cm. If the distance between the slits is 1 mm, then the wavelength of the light will be ______nm.
Using Young's double slit experiment, a monochromatic light of wavelength 5000 Å produces fringes of fringe width 0.5 mm. If another monochromatic light of wavelength 6000Å is used and the separation between the slits is doubled, then the new fringe width will be :
- (A)0.5 mm
- (B)1.0 mm
- (C)0.6 mm
- (D)0.3 mm
In young's double slit experiment performed using a monochromatic light of wavelength λ, when a glass plate (μ = 1.5) of thickness xλ is introduced in the path of the one of the interfering beams, the intensity at the position where the central maximum occurred previously remains unchanged. The value of x will be:
- (A)3
- (B)2
- (C)1.5
- (D)0.5
In a Young's double slit experiment, an angular width of the fringe is 0.35° on a screen placed at 2 m away for particular wavelength of 450 nm. The angular width of the fringe, when whole system is immersed in a medium of refractive index 7/5, is . The value of α is ________
The aperture of the objective is 24.4 cm. The resolving power of this telescope. If a light of wavelength 2440 Å is used to see the object will be
- (A)
- (B)
- (C)
- (D)
If a wave gets refracted into a denser medium, then which of the following is true?
- (A)wavelength speed and frequency decreases.
- (B)wavelength increases, speed decreases and frequency remains constant.
- (C)wavelength and speed decreases but frequency remains constant.
- (D)wavelength, speed and frequency increases.
In Young's double slit experiment the two slits are 0.6 mm distance apart. Interference pattern is observed on a screen at a distance 80 cm from the slits. The first dark fringe is observed on the screen directly opposite to one of the slits. The wavelength of light will be ______ nm.
For a specific wavelength 670 nm of light coming from a galaxy moving with velocity v, the observed wavelength is 670.7 nm.
The value of v is :
- (A)3 × ms
- (B)3 × ms
- (C)3.13 × ms
- (D)4.48 × ms
The two light beams having intensities I and 9I interfere to produce a fringe pattern on a screen. The phase difference between the beams is at point P and π at point Q. Then the difference between the resultant intensities at P and Q will be :
- (A)2 I
- (B)6 I
- (C)5 I
- (D)7 I
The interference pattern is obtained with two coherent light sources of intensity ratio 4 :1. And the ratio is . Then, the value of x will be equal to :
- (A)3
- (B)4
- (C)2
- (D)1
A light whose electric field vectors are completely removed by using a good Polaroid, allowed to incident on the surface of the prism at Brewster's angle. Choose the most suitable option for the phenomenon related to the prism.
- (A)Reflected and refracted rays will be perpendicular to each other
- (B)Wave will propagate along the surface of prism
- (C)No refraction, and there will be total reflection of light.
- (D)No reflection and there will be total transmission of light.
Two light beams of intensities in the ratio of 9 : 4 are allowed to interfere. The .ratio of the intensity of maxima and minima will be :
- (A)2 : 3
- (B)16 : 81
- (C)25 : 169
- (D)25 : 1
Sodium light of wavelengths 650 nm and 655 nm is used to study diffraction at a single slit of aperture 0.5 mm. The distance between the slit and the screen is 2.0 m. The separation between the positions of the first maxima of diffraction pattern obtained in the two cases is ______ m.
The width of one of the two slits in a Young's double slit experiment is three times the other slit. If the amplitude of the light coming from a slit is proportional to the slit-width, the ratio of minimum to maximum intensity in the interference pattern is x : 4 where x is ________ .
In a Young's double slit experiment, the slits are separated by 0.3 mm and the screen is 1.5 m away from the plane of slits. Distance between fourth bright fringes on both sides of central bright is 2.4 cm. The frequency of light used is______ 10 Hz.
The light waves from two coherent sources have same intensity = = . In interference pattern the intensity of light at minima is zero. What will be the intensity of light at maxima ?
- (A)
- (B)2
- (C)5
- (D)4
A source of light is placed in front of a screen. Intensity of light on the screen is I. Two Polaroids and are so placed in between the source of light and screen that the intensity of light on screen is I/2. should be rotated by an angle of ........... (degrees) so that the intensity of light on the screen becomes .
White light is passed through a double slit and interference is observed on a screen 1.5 m away. The separation between the slits is 0.3 mm. The first violet and red fringes are formed 2.0 mm and 3.5 mm away from the central white fringes. The difference in wavelengths of red and voilet light is ......... nm.
In Young's double slit experiment, if the source of light changes from orange to blue then:
- (A)the distance between consecutive fringes will decrease.
- (B)the distance between consecutive fringes will increase.
- (C)the central bright fringe will become a dark fringe.
- (D)the intensity of the minima will increase.
The difference in the number of waves when yellow light propagates through air and vacuum columns of the same thickness is one. The thickness of the air column is ________ mm. [Refractive index of air = 1.0003 , wavelength of yellow light in vacuum = 6000 Å ]
In the Young's double slit experiment, the distance between the slits varies in time as ; where , and are constants. The difference between the largest fringe width and the smallest fringe width obtained over time is given as :
- (A)
- (B)
- (C)
- (D)
With what speed should a galaxy move outward with respect to earth so that the sodium line at wavelength is observed at ?
- (A)322 km / sec
- (B)296 km / sec
- (C)306 km / sec
- (D)336 km / sec
A galaxy is moving away from the earth at a speed of 286 kms. The shift in the wavelength of a red line at 630 nm is x × 10 m. The value of x, to the nearest integer, is______.
[Take the value of speed of light c, as 3 × 10 ms]
In Young's double slit arrangement, slits are separated by a gap of 0.5 mm, and the screen is placed at a distance of 0.5 m from them. The distance between the first and the third bright fringe formed when the slits are illuminated by a monochromatic light of 5890 Å is :-
- (A)1178 × 10 m
- (B)1178 × 10 m
- (C)1178 × 10 m
- (D)5890 × 10 m
A fringe width of 6 mm was produced for two slits separated by 1 mm apart. The screen is placed 10 m away. The wavelength of light used is 'x' nm. The value of 'x' to the nearest integer is ______.
In a Young's double slit experiment two slits are separated by 2 mm and the screen is placed one meter away. When a light of wavelength 500 nm is used, the fringe separation will be :
- (A)0.75 mm
- (B)0.50 mm
- (C)1 mm
- (D)0.25 mm
Consider the diffraction pattern obtained from the sunlight incident on a pinhole of diameter 0.1 µm. If the diameter of the pinhole is slightly increased, it will affect the diffraction pattern such that:
- (A)its size decreases, but intensity increases
- (B)its size increases, but intensity decreases
- (C)its size increases, and intensity increases
- (D)its size decreases, and intensity decreases
Two coherent light sources having intensity in the ratio 2x produce an interference pattern. The ratio will be :
- (A)
- (B)
- (C)
- (D)
If the source of light used in a Young's double slit experiment is changed from red to violet:
- (A)the fringes will become brighter.
- (B)consecutive fringe lineswill come closer.
- (C)the central bright fringe will become a dark fringe.
- (D)the intensity of minima will increase.
An unpolarized light beam is incident on the polarizer of a polarization experiment and the intensity of light beam emerging fromthe analyzer is measured as 100 Lumens. Now, if the analyzer is rotated around the horizontal axis (direction of light) by 30° in clockwise direction, the intensity of emerging light will be__________ Lumens.
In a Young's double slit experiment, the width ofthe one of the slit is three times the other slit. The amplitude of the light coming from a slit is proportional to the slit-width. Find the ratio of the maximum to the minimum intensity in the interference pattern.
- (A)4 : 1
- (B)2 : 1
- (C)3 : 1
- (D)1 : 4
A parallel beam of light strikes a piece of transparent glass having cross section as shown in the figure below. Correct shape of the emergent wavefront will be (figures are schematic and not drawn to scale)-
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
In the figure below, P and Q are two equally intense coherent sources emitting radiation of wavelength 20 m. The separation between P and Q is 5 m and the phase of P is ahead of that of Q by . A, B and C are three distinct points of observation, each equidistant from the midpoint of PQ. The intensities of radiation at A, B, C will be in the ratio:
- (A)0 : 1 : 4
- (B)2 : 1 : 0
- (C)0: 1 : 2
- (D)4 : 1 : 0
A Young's double-slit experiment is performed using monochromatic light of wavelength λ. The intensity of light at a point on the screen, where the path difference is λ, is K units. The intensity of the light at a point where the path difference is is given by , where 'n' is an integer. The value of 'n' is ______.
A beam of plane polarized light of large cross-sectional area and uniform intensity of 3.3 Wm falls normally on a polarizer (cross sectional area m) which rotates about its axis with an angular speed of 31.4 rad/s. The energy of light passing through the polariser per revolution, is close to:
- (A) J
- (B) J
- (C) J
- (D) J
Two light waves having the same wavelength λ in vacuum are in phase initially. Then the first wave travels path through a medium of refractive index while the second wave travels a path of length through a medium of refractive index . After this the phase difference between the two waves is:
- (A)
- (B)
- (C)
- (D)
In a Young's double slit experiment, light of 500 nm is used to produce an interference pattern. When the distance between the slits is 0.05 mm, the angular width (in degree) of the fringes formed on the distance screen is close to:
- (A)1.7°
- (B)0.07°
- (C)0.57°
- (D)0.17°
The aperture diameter of a telescope is 5m. The separation between the moon and the earth is km. With light of wavelength of 5500 Ä, the minimum separation between objects on the surface of moon, so that they are just resolved, is close to:
- (A)200 m
- (B)600 m
- (C)60 m
- (D)20 m
In a Young's double's slit experiment 15 fringes are observed on a small portion of the screen when light of wavelength 500 nm is used. Ten fringes are observed on the same section of the screen when another light source of wavelength is used. Then the value of is (in nm) __________.
In a double-slit experiment, at a certain point on the screen the path difference between the two interfering waves is th of a wavelength. The ratio of the intensity of light at that point to that at the centre of a bright fringe is:
- (A)0.672
- (B)0.568
- (C)0.760
- (D)0.853
A polarizer-analyser set is adjusted such that the intensity of light coming out of the analyser is just 10% of the original intensity. Assuming that the polarizer-analyser set does not absorb any light, the angle by which the analyser need to be rotated further to reduce the output intensity to be zero is
- (A)
- (B)
- (C)
- (D)
In a Young's double slit experiment, the separation between the slits is 0.15 mm. In the experiment, a source of light of wavelength 589 nm is used and the interference pattern is observed on a screen kept 1.5 m away. The separation between the successive bright fringes on the screen is:
- (A)4.9 mm
- (B)6.9 mm
- (C)3.9 mm
- (D)5.9 mm
Visible light of wavelength cm falls normally on a single slit and produces a diffraction pattern. It is found that the second diffraction minimum is at 60° from the central maximum. If the first minimum is produced at then is close to:
- (A)
- (B)
- (C)
- (D)
In a Young's double slit experiment, the slit separation d is 0.3 mm and the screen distance D is 1 m. A parallel beam of light of wavelength 600 nm is incident on the slits at angle as shown in figure. On the screen, the point O is equidistant from the slits and distance PO is 11.0 mm. Which of the following statements(s) is/are correct ?
- (A)For degree, there will be destructive interference at point O.
- (B)Fringe spacing depends on .
- (C)For degree, there will be destructive interference at point P.
- (D)For , there will be constructive interference at point P.
A system of three polarizers P, P, P is set up such that the pass axis of P is crossed with respect to that of P. The pass axis of P is inclined at 60º to the pass axis of P. When a beam of unpolarized light of intensity I0 is incident on P, the intensity of light transmitted by the three polarizers is I. The ratio (I/I) equals (nearly) :
- (A)10.67
- (B)1.80
- (C)5.33
- (D)16.00
The value of numerical aperature of the objective lens of a microscope is 1.25. If light of wavelength 5000 Å is used, the minimum separation between two points, to be seen as distinct, will be :
- (A)0.48 μm
- (B)0.38 μm
- (C)0.24 μm
- (D)0.12 μm
In a double slit experiment, when a thin film of thickness t having refractive index is introduced in front of one of the slits, the maximum at the centre of the fringe pattern shifts by one fringe width. The value of t is ( is the wavelength of the light used) :
- (A)
- (B)
- (C)
- (D)
In a Young's double slit experiment the ratio of the slit's width is 4 : 1. The ratio of the intensity of maxima to minima, close to central fringe on the screen will be
- (A)
- (B)25 : 9
- (C)9 : 1
- (D)4:1
Diameter of the objective lens of a telescope is 250 cm. For light of wavelength 600 nm. Coming from a distant object, the limit of resolution of the telescope is close to:-
- (A) rad
- (B) rad
- (C) rad
- (D) rad
In an interference experiment the ratio of amplitudes of coherent waves is . The ratio of maximum and minimum intensities of fringes will be:
- (A)9
- (B)4
- (C)18
- (D)2
Calculate the limit of resolution of a telescope objective having a diameter of 200 cm, if it has to detect light of wavelength 500 nm coming from a star.
- (A) radian
- (B) radian
- (C) radian
- (D) radian
A light wave is incident normally on a glass slab of refractive index 1.5. If 4% of light gets reflected and the amplitude of the electric field of the incident light is 30 V/m, then the amplitude of the electric field for the wave propagating in the glass medium will be:
- (A)30 V/m
- (B)10 V/m
- (C)24 V/m
- (D)6 V/m
In a Young's double slit experiment, the path difference, at a certain point on the screen, between two interfering waves is 1/8 of wavelength. The ratio of the intensity at this point to that at the centre of a bright fringe is close to:
- (A)0.74
- (B)0.85
- (C)0.94
- (D)0.80
In a double – slit experiment, green light (5303 Å) falls on a double slit having a separation of 19.44 μm and a width of 4.05μm. The number of bright fringes between the first and the second diffraction minima is:
- (A)10
- (B)05
- (C)04
- (D)09
In a Young's double slit experiment with slit separation 0.1 mm, one observes a bright fringe at angle rad by using light of wavelength . When the light of wavelength is used a bright fringe is seen at the same angle in the same set up. Given that and are in visible range (380 nm to 740 nm), their values are:
- (A)625 nm, 500 nm
- (B)380 nm, 525 nm
- (C)380 nm, 500 nm
- (D)400 nm, 500 nm
Two coherent sources produce waves of different intensities which interfere. After interference, the ratio of the maximum intensity to the minimum intensity is 16. The intensity of the waves are in the ratio:
- (A)16 : 9
- (B)25 : 9
- (C)4 : 1
- (D)5 : 3
Consider a tank made of glass (refractive index 1.5) with a thick bottom. It is filled with a liquid of refractive index . A student finds that, irrespective of what the incident angle I (see figure) is for a beam of light entering the liquid, the light reflected from the liquid glass interface is never completely polarized. For this to happen, the minimum value of is
- (A)
- (B)
- (C)
- (D)
In a Young's double slit experiment, the slits are placed 0.320 mm apart. Light of wavelength nm is incident on the slits. The total number of bright fringes that are observed in the angular range is:
- (A)640
- (B)320
- (C)321
- (D)641
Two coherent monochromatic point sources and of wavelength nm are placed symmetrically on either side of the centre of the circle as shown. The sources are separated by a distance mm. This arrangement produces interference fringes visible as alternate bright and dark spots on the circumference of the circle. The angular separation between two consecutive bright spots is . Which of the following options is/are correct?
- (A)A dark spot will be formed at the point
- (B)At the order of the fringe will be maximum
- (C)The total number of fringes produced between and in the first quadrant is close to 3000
- (D)The angular separation between two consecutive bright spots decreases as we move from to along the first quadrant
While conducting the Young's double slit experiment, a student replaced the two slits with a large opaque plate in the x-y plane containing two small holes that act as two coherent point sources (, ) emitting light of wavelength 600 nm. The student mistakenly placed the screen parallel to the x-z plane (for z > 0) at a distance D = 3 m from the mid-point of , as shown schematically in the figure. The distance between the sources d = 0.6003 mm. The origin O is at the intersection of the screen and the line joining . which of the following is(are) true of the intensity pattern on the screen?
- (A)Hyperbolic bright and dark bands with foci symmetrically placed about O in the x-direction
- (B)Semi circular bright and dark bands centred at point O
- (C)The region very close to the point O will be dark
- (D)Straight bright and dark bands parallel to the x-axis
A Young's double slit interference arrangement with slits and is immersed in water (refractive index = 4/3) as shown in the figure. The positions of maxima on the surface of water are given by , where is the wavelength of light in air (refractive index = 1), is the separation between the slits and is an integer. The value of is
A light source, which emits two wavelengths and , is used in a Young's double slit experiment. If recorded fringe widths for and are and and the number of fringes for them within a distance on one side of the central maximum are and , respectively, then
- (A)
- (B)
- (C)From the central maximum, maximum of overlaps with minimum of
- (D)The angular separation of fringes for is greater than
In the Young’s double slit experiment using a monochromatic light of wavelength , the path difference (in terms of an integer n) corresponding to any point having half the peak intensity is
- (A)
- (B)
- (C)
- (D)
Wave Optics — frequently asked
How many questions from Wave Optics appear in JEE?
Wave Optics has appeared in 130 of the last 186 JEE Main and JEE Advanced papers — about 70% of them — contributing 151 questions in total across those papers.
Is Wave Optics an important chapter for JEE?
Judged by how often it is actually tested, it appears in roughly 70% of papers. Chapters above about 50% are effectively guaranteed to show up every session, so they repay thorough preparation; lower-frequency chapters are better treated as targeted revision.
Where do these Wave Optics questions come from?
Every question is from an official JEE Main or JEE Advanced paper, transcribed from the original paper and tagged to this chapter. Answers follow the official answer key.
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