Wave Optics

In interference experiment the path difference between two interfering waves at a point \(A\) on the screen is \(\lambda /3\), where \(\lambda\) is the wavelength of these waves, and at another point \(B\) the path difference is \(\lambda /6\). The ratio of intensities at points \(A\) and \(B\) is _______.

[JEE Main 2026, 6 Apr (Shift 1)]

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:

[JEE Main 2025, 4 Apr (Shift 1)]

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 ring of radius 3 cm has a soap film which is getting evaporated. Light of wavelength \(\lambda=580 \mathrm{~nm}\) gives minimum transmission every 12 s . Find the rate of evaporation. (Refractive index=1.45)(Shift - II Memory Based)

The width of one of the two slits in Young's double slit experiment is d while that of the other slit is \(x\mathrm{d}\). If the ratio of the maximum to the minimum intensity in the interference pattern on the screen is \(9:4\) then what is the value of \(x\) ?
(Assume that the field strength varies according to the slit width.)

[JEE Main 2025, 23 Jan (Shift 2)]

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion-(A) : If Young's double slit experiment is performed in an optically denser medium than air, then 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 from the options given below :

[JEE Main 2025, 22 Jan (Shift 1)]

Young's double slit inteference 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 on a screen placed behind the plane of slits at a distance of 0.72 m, will be :

The diffraction pattern of a light of wavelength \(400 \mathrm{~nm}\) diffracting from a slit of width \(0.2 \mathrm{~mm}\) is focused on the focal plane of a convex lens of focal length \(100 \mathrm{~cm}\). The width of the \(1^{\text {st }}\) secondary maxima will be :

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 :

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 \(7\lambda /4\). The ratio of intensity of fringe at this point with respect to the maximum intensity of the fringe is:

Light emerges out of a convex lens when a source of light kept at its focus. The shape of wavefront of the light is :

Light emerges out of a convex lens when a source of light kept at its focus. The shape of wavefront of the light is :

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

[JEE Main 2025, 8 Apr (Shift 1)]

The maximum intensity in a Young's double slit experiment is \({I}_{\mathrm{o}}\). Distance between the slits (d) is \(5\lambda\), where \(\lambda\) is the wavelength of light used. The intensity of the fringe, exactly opposite to one of the slits on the screen, placed at \(D=10d\) is ____ .

[JEE Main 2026, 5 Apr (Shift 2)]

Two plane polarized light waves combine at a certain point whose electric field components are
\({\mathrm{E}}_{1}={\mathrm{E}}_{0}\mathrm{sinωt}\\ {\mathrm{E}}_{2}={\mathrm{E}}_{0}\sin \left(\mathrm{ωt}+\frac{\pi }{3}\right)\)
Find the amplitude of the resultant wave.

Young's double slit inteference 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 on a screen placed behind the plane of slits at a distance of 0.72 m, will be :

[JEE Main 2025, 24 Jan (Shift 2)]

The Young's double slit interference experiment is performed using light consisting of 480 nm and 600 nm wavelengths to form interference patterns. 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

[JEE Main 2025, 24 Jan (Shift 1)]

The width of one of the two slits in Young's double slit experiment is d while that of the other slit is \(x\mathrm{d}\). If the ratio of the maximum to the minimum intensity in the interference pattern on the screen is \(9:4\) then what is the value of \(x\) ?
(Assume that the field strength varies according to the slit width.)

[JEE Main 2025, 23 Jan (Shift 2)]

A glass slab of refractive index \({\mu }_{0}=1.44\) is coated with a thin film of refractive index \({\mu }_{f}=2\). The minimum thickness of the film, so that maximum transmission of green light of wavelength λ = 5000A˚ (incident normally) takes place, is:

Two plane polarized light waves combine at a certain point whose electric field components are
\({\mathrm{E}}_{1}={\mathrm{E}}_{0}\mathrm{sinωt}\\ {\mathrm{E}}_{2}={\mathrm{E}}_{0}\sin \left(\mathrm{ωt}+\frac{\pi }{3}\right)\)
Find the amplitude of the resultant wave.

[JEE Main 2025, 7 Apr (Shift 1)]

When a polaroid sheet is rotated between two crossed polaroids then the transmitted light intensity will be maximum for a rotation of :

[JEE Main 2024, 27 Jan (Shift 2)]

When a polaroid sheet is rotated between two crossed polaroids then the transmitted light intensity will be maximum for a rotation of :

[JEE Main 2024, 27 Jan (Shift 2)]

In a Young's Double-Slit Experiment (YDSE), lights of wavelengths \(600\text{ }\text{nm}\) and \(500\text{ }\text{nm}\) are used. What is the minimum order of the bright fringe of 500nm that coincides with the dark fringe of \(600\text{ }\text{nm}\)?

A ring of radius 3 cm has a soap film which is getting evaporated. Light of wavelength \(\lambda=580 \mathrm{~nm}\) gives minimum transmission every 12 s . Find the rate of evaporation. (Refractive index=1.45)(Shift - II Memory Based)

In a Young's Double Slit Experiment (YDSE), for a wavelength \({\lambda }_{1}=600nm\), the 10th bright fringe is observed at a distance of 10 mm from the central maximum.For a new wavelength \({\lambda }_{2}=660nm\), what will be the distance of the 10th bright fringe from the central maximum?

(Shift - I Memory based)

The Young's double slit interference experiment is performed using light consisting of 480 nm and 600 nm wavelengths to form interference patterns. 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

In Young’s double slit experiment, the fringe width of the interference pattern produced on the screen is 2.4 \(\mu \mathrm{m}\). If the experiment is carried out in another medium having refractive index 1.2, the fringe width will be _______ \(\mu \mathrm{m}\).

[JEE Main 2026, 5 Apr (Shift 1)]

A slit of width a is illuminated by light of wavelength \(\lambda\) The linear separation between \({1}^{st}\) and \({3}^{rd}\)minima in the diffraction pattern produced on a screen placed at a distance D from the slit system is ____.

[04 April, 2026 (Shift-I)]

A glass slab of refractive index \({\mu }_{0}=1.44\) is coated with a thin film of refractive index \({\mu }_{f}=2\). The minimum thickness of the film, so that maximum transmission of green light of wavelength λ = 5000A˚ (incident normally) takes place, is:

(Shift II Memory Based)

In a Young's Double Slit Experiment (YDSE), for a wavelength \({\lambda }_{1}=600nm\), the 10th bright fringe is observed at a distance of 10 mm from the central maximum.For a new wavelength \({\lambda }_{2}=660nm\), what will be the distance of the 10th bright fringe from the central maximum?

(Shift - I Memory based)

In Young’s double slits experiment, the position of 5^th bright fringe from the central maximum is 5 cm. The distance between slits and the screen is 1m and wavelength of monochromatic light used is 600nm. The separation between the slits is:

[JEE Main 2023, 25 Jan (Shift 1)]

A scientist is observing a bacteria using a compound microscope. For better analysis and to improve its resolving power, he should: (Select the best option)

[JEE Main 2023, 29 Jan (Shift 2)]

The ratio of intensities at two points \(P\) and \(Q\) on the screen in a Young's double slit experiment where phase difference between two waves of same amplitude are \(\pi / 3\) and \(\pi / 2\), respectively are:

Two coherent sources of light interfere and produce fringe pattern on a screen. For central maximum, the phase difference between the two waves will be.

Two light waves having the same wavelength \(\lambda\) in vacuum are in phase initially. Then the first wave travels a path \( \mathrm{L}_1\) through a medium of refractive index \(n_1\) while the second wave travels a path of length \(L_2\) through a medium of refractive index \(n_2\). After this the phase difference between the two waves is :

In the Young's double slit experiment, the distance between the slits varies in time as \(d(t)=d_0+a_0 \sin \omega t\); where \(d_0, \omega\) and \(a_0\) are constants. The difference between the largest fringe width and the smallest fringe width obtained over time is given as:

Two polaroide \(A\) and \(B\) are placed in such a way that the pass-axis of polaroids are perpendicular to each other. Now, another polaroid \(C\) is placed between \(A\) and \(B\) bisecting the angle between them. If intensity of unpolarised light is \(I_0\) then intensity of transmitted light after passing through polaroid B will be:

[JEE Main 2023, 31 Jan (Shift 1)]

For Young's double slit experiment, two statements are given below :
Statement I : If screen is moved away from the plane of slits, angular separation of the fringes remains constant.

Statement II : If the monochromatic source is replaced by another monochromatic source of larger wavelength, the angular separation of fringes decreases.

In the light of the above statements, choose the correct answer from the options given below :

[NEET 2023]

In Young's double slit experiment, if the source of light changes from orange to blue then:

Two coherent light sources having intensity in the ratio \(2x\) produce an interference pattern. The ratio \(\ \frac{I_{\max }-I_{\min }}{I_{\max }+I_{\min }}\) will be:

[JEE Main 2021, 25 Feb (Shift 1)]

Two polaroids \(A\) and \(B\) are placed in such a way that the pass-axis of polaroids are perpendicular to each other. Now, another polaroid \(C\) is placed between \(A\) and \(B\) bisecting the angle between them. If intensity of unpolarised light is \(I_0\) then intensity of transmitted light after passing through polaroid B will be:

The light waves from two coherent sources have same intensity \(I_1=I_2=I_0\). In interference pattern the intensity of light at minima is zero. What will be the intensity of light at maxima?

' \(n\) ' polarizing sheets are arranged such that each makes an angle \(45^{\circ}\) with the preceeding sheet. An unpolarized light of intensity \(I\) is incident into this arrangement. The output intensity is found to be \(\frac{I}{64}\). The value of \(n\) will be:

[JEE Main 2023, 1 Feb (Shift 1)]