Wave Optics — JEE Main PYQs

In a double slit experiment shown in figure, when light of wavelength 400 nm is used, dark fringe is observed at P. If $\mathrm{D}=0.2\mathrm{m}$, the minimum distance between the slits $S_1$ and $S_2$ is $\_\_\_\_$ mm.

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 ${\mathrm{I}}_1$ (b) Waves are coherent is $I_2$ and differ in phase by $60^{\circ }$. If $\frac{I_1}{I_2}=\frac{10}{x}$ then …

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:

In Young's double slit experiment, monochromatic light of wavelength $5000\mathring{A}$ 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 i …

A monochromatic light of wavelength $6000\mathring{A}$ is incident on the single slit of width 0.01 mm . If the diffraction pattern is formed at the focus of the convex lens of focal length 20 cm , the linear width of the central maximum is :

A beam of unpolarised light of intensity ${\mathrm{I}}_0$ is passed through a polaroid A and then through another polaroid B which is oriented so that its principal plane makes an angle of $45^{\circ }$ relative to that of A. The intensity of emergent light is:

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

When unpolarized light is incident at an angle of $60^{\circ }$ on a transparent medium from air. The reflected ray is completely polarized. The angle of refraction in the medium is

The width of fringe is 2 mm on the screen in a double slits experiment for the light of wavelength of 400 nm . The width of the fringe for the light of wavelength 600 nm will be:

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 wavele …

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 cen …

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 wave of same amplitude are $\pi /3$ and $\pi /2$, respectively are

In a Young's double slits 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 single slit of width $a$ is illuminated by a monochromatic light of wavelength 600 nm. The value of 'a' for which first minimum appears at $\theta =30^{\circ }$ on the screen will be :

'$n$' polarizing sheets are arranged such that each makes an angle $45^{\circ }$ with the proceeding 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:

Given below are two statements :

Statement I: If the Brewster's angle for the light propagating from air to glass is ${\theta }_{\mathrm{B}}$, then Brewster's angle for the light propagating from glass to air is $\frac{\pi }{2}-{\theta }_{\mathrm{B}}$.
Statement II : The Brewster's …

In Young's double slits experiment, the position of $5^{\text{th}}$ 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:

In a Young's double slit experiment, two slits are illuminated with a light of wavelength 800 nm . The line joining ${\mathrm{A}}_1\mathrm{P}$ is perpendicular to ${\mathrm{A}}_1{\mathrm{A}}_2$ as shown in the figure. If the first minimum is detected at P , the value of slits …

As shown in figures, three identical polaroids $P_1$, $P_2$ and $P_3$ are placed one after another. The pass axis of $P_2$ and $P_3$ are inclined at angle of $60^{\circ }$ and $90^{\circ }$ with respect to axis of $P_1$. The source S has an intensity of …

Unpolarised light is incident on the boundary between two dielectric media, whose dielectric constants are 2.8 (medium-1) and 6.8 (medium 2), respectively. To satisfy the condition, so that the reflected and refracted rays are perpendicular to each other, the angle of incidence s …

In a Young's double slit experiment, the intensities at two points, for the path difference $\frac{\lambda }{4}$ and $\frac{\lambda }{3}$ ( $\lambda$ being the wavelength of light used) are ${\mathrm{I}}_1$ and ${\mathrm{I}}_2$ respectively. If ${\mathrm{I}}_0$ denotes the intensit …

In Young's double slit experiment, two slits $S_1$ and $S_2$ are 'd' distance apart and the separation from slits to screen is D (as shown in figure). Now if two transparent slabs of equal thickness 0.1 mm but refractive index 1.51 and 1.55 are introduced in the path of beam ( …

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 angle between them. If intensity of unpolarised light is $I_0$ then intensity of transmitted light after pas …

Two light waves of wavelengths 800 and 600 nm are used in Young's double slit experiment to obtain interference fringes on a screen placed 7 m away from plane of slits. If the two slits are separated by 0.35 mm, then shortest distance from the central bright maximum to the point …

As shown in the figure, in Young's double slit experiment, a thin plate of thickness $\mathrm{t}=10\mu \mathrm{m}$ and refractive index $\mu =1.2$ is inserted infront of slit ${\mathrm{S}}_1$. The experiment is conducted in air ($\mu =1$) and uses a monochromatic light of wavelen …

An unpolarised light beam of intensity $2{\mathrm{I}}_0$ 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 $30^{\circ }$ relative to that of P. The intensity of the emergent light is

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 wavelengt …

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 $\pi /2$ and $\pi /3$ at points A and B respectively. The difference between the resultant intensities at the two points is xI. T …

Two coherent sources of light interfere. The intensity ratio of two sources is $1:4$. For this interference pattern if the value of $\frac{I_{\text{max}}+I_{\text{min}}}{I_{\text{max}}-I_{\text{min}}}$ is equal to $\frac{2\alpha +1}{\beta +3}$, then $\frac{\alpha }{\beta }$ will be:

In young's double slit experiment, the fringe width is 12 mm. If the entire arrangement is placed in water of refractive index $\frac{4}{3}$, then the fringe width becomes (in mm)

In young's double slit experiment performed using a monochromatic light of wavelength $\lambda$, when a glass plate $(\mu =1.5)$ of thickness $\mathrm{x}\lambda$ is introduced in the path of the one of the interfering beams, the intensity at the position where the central maximum …

In a Young's double slit experiment, an angular width of the fringe is $0.35^{\circ }$ 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 $\frac{1}{\alpha }$. …

The aperture of the objective is 24.4 cm. The resolving power of this telescope, if a light of wavelength $2440\mathring{A}$ is used to see the object will be

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 $5\times 10^{-2}\mathrm{m}$ towards the slits, the change in fringe width is $3\times 10^{-3}\mathrm{cm}$. If th …

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 $6000\mathring{A}$ is used and the separation between the slits is doubled, then the new fringe width will be :

In free space, an electromagnetic wave of 3 GHz frequency strikes over the edge of an object of size $\frac{\lambda }{100}$, where $\lambda$ is the wavelength of the wave in free space. The phenomenon, which happens there will be:

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 __\ …

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 $\pi$. The difference of resultant intensities, at the point A and B, will be ______ I.

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 ____ …

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 :

The interference pattern is obtained with two coherent light sources of intensity ratio $4:1$. And the ratio $\frac{I_{\text{max }}+I_{\text{min }}}{I_{\text{max }}-I_{\text{min }}}$ is $\frac{5}{x}$. Then, the value of $x$ will be equal to:

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.

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 $\frac{\pi }{2}$ at point P and $\pi$ at point Q. Then the difference between the resultant intensities at P and Q will be:

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 …

In a Young's double slit experiment, the width of the 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.

An unpolarized light beam is incident on the polarizer of a polarization experiment and the intensity of light beam emerging from the analyzer is measured as 100 Lumens. Now, if the analyzer is rotated around the horizontal axis (direction of light) by $30^{\circ }$ in clockwise d …

A source of light is placed in front of a screen. Intensity of light on the screen is I. Two Polaroids $P_1$ and $P_2$ are so placed in between the source of light and screen that the intensity of light on screen is $1/2$. $P_2$ should be rotated by an angle of _____ (deg …

If the source of light used in a Young's double slit experiment is changed from red to violet:

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?

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