Optics PYQ — Page 18

On a hot summer night, the refractive index of air is the smallest near the ground and increases with a height from the ground. When a light beam is directed horizontally, the Huygens' principle leads us to conclude that as it travels, the light beam,

Monochromatic light is incident on a glass prism of angle A. If the refractive index of the material of the prism is $\mu$ , a ray, incident at an angle $\theta$ , on the face AB would get transmitted through the face AC of the prism provided: 

In a Young's double slit experiment with light of wavelength $\lambda ,$ the separation of slits is $d$ and distance of screen is $D$ such that $D\gg d\gg \lambda$ . If the Fringe width is $\beta$ , the distance from point of maximum intensity to the point where intensity falls to half of the maximum intensity on either side is:

Assuming that the human pupil has a radius of $0.25 \mathrm{cm}$ and a comfortable viewing distance of $25\mathrm{cm}$. The minimum separation between two point objects that the human eye can resolve for the light of wavelength $500\mathrm{nm}$ is

A thin convex lens of focal length $f$ is put on a plane mirror as shown in the figure. When an object is kept at a distance $a$ from the lens-mirror combination, its image is formed at a distance $\frac{a}{3}$ in front of the combination. The value of $a$ is: 

A telescope has an objective lens of focal length $150\mathrm{cm}$ and an eyepiece of focal length $5\mathrm{cm}$. If a $50m$ tall tower at a distance of $1\mathrm{km}$ is observed through this telescope in a normal setting, the angle formed by the image of the tower is $\theta$, then $\theta$ is close to

A parallel beam of electrons travelling in x - direction falls on a slit of width d (see figure). If after passing the slit, an electron acquires momentum ${p}_{y}$ in the y - direction then for a majority of electrons passing through the slit (h is Planck's constant): 

Using monochromatic light of wavelength $\lambda$, an experimentalist sets up the Young's double slit experiment in three ways as shown. If she observes that $y⁡ = {\beta }^{'}$, the wavelength of light used is :   

Two monochromatic light beams of intensity 16 and 9 units are interfering. The ratio of intensities of bright and dark parts of the resultant pattern is:

Two beams, A and B of plane polarized light with mutually perpendicular planes of polarization are seen through a polaroid. From the position when the beam A has maximum intensity (and beam B has zero intensity), a rotation of polaroid through 30$^{o}$ makes the two beams appear equally bright. If the initial intensities of the two beams are I$_{A}$ and I$_{B}$ respectively, then $\frac{ {\text{I}}_{\text{A}} }{ {\text{I}}_{\text{B}} }$ equals :

The refractive index of the material of a concave lens is $\mu$. It is immersed in a medium of refractive index $\mu_1$. A parallel beam of light is incident on the lens. The path of the emergent rays when $\mu_1>\mu$ is:

The focal lengths of objective lens and eye lens of a Galilean Telescope are respectively 30 cm and 3.0 cm. Telescope produces virtual, erect image of an object situated far away from it at least distance of distinct vision from the eye lens. In this condition the Magnifying Power of the Galilean Telescope should be :

Interference pattern is observed at ' $\mathrm{P}$ ' due to superimposition of two rays coming out from a source ' $S$ ' as shown in the figure. The value of ' $\mathrm{l}$ ' for which maxima is obtained at ' $\mathrm{P}$ ' is: ( $\mathrm{R}$ is perfect reflecting surface) 

In Young’s double-slit experiment, the distance between the two identical slits is$6.1$ times larger than the slit width. Then the number of intensity maxima observed within the central maximum of the single-slit diffraction pattern is :

In an experiment of single slit diffraction pattern, first minimum for red light coincides with first maximum of some other wavelength. If wavelength of red light is $6600 Å$, then wavelength of first maximum will be:

In a compound microscope the focal length of objective lens is $1.2 \mathrm{~cm}$ and focal length of eye piece is $3.0 \mathrm{~cm}$. When object is kept at $1.25 \mathrm{~cm}$ in front of objective, final image is formed at infinity. Magnifying power of the compound microscope should be:

An object is located in a fixed position in front of a screen. Sharp image is obtained on the screen for two positions of a thin lens separated by 10 $\mathrm{cm}$. The size of the images in two situations are in the ratio $3: 3$. What is the distance between the screen and the object?

A thin convex lens made from crown glass $( \mu = \frac{ 3 }{ 2 } )$ has focal length $f⁡$. When it is measured in two different liquids having refractive indices $\frac{ 4 }{ 3 }$ and $\frac{ 5 }{ 3 }$, it has the focal lengths ${ f⁡ }_{1}$ and ${ f⁡ }_{2}$ respectively. The correct relation between the focal lengths is :

A ray of light is incident from a denser to a rarer medium. The critical angle for total internal reflection is ${\theta }_{\text{iC}}$ and Brewster's angle of incidence is ${\theta }_{\text{iB}}$, such that $\frac{\text{sin}{\theta }_{\text{iC}}}{\text{sin}{\theta }_{\text{iB}}}=\eta =1\text{.}28$. The relative refractive index of the two media is

A green light is incident from the water to the air - water interface at the critical angle $({\theta }_{c})$. Select the correct statement.

A diver looking up through the water sees the outside world contained in a circular horizon. The refractive index of water is $\frac{ 4 }{ 3 }$, and the diver's eyes are $15\mathrm{cm}$ below the surface of the water. Then the radius of the circle is :

Two coherent point sources ${S}_{1}$ and ${S}_{2}$ are separated by a small distance $d$ as shown in the figure. The fringes obtained on the screen will be 

This question has Statement-1 and Statements2. Of the four choices given after the Statements, choose the one that best describes the two Statements. Statement-1 : Out of radio waves and microwaves, the radio waves undergo more diffraction. Statement-2 : Radio waves have greater frequency compared to microwaves.

This question has Statement-1 and Statement-2. Of the four choices given after the Statements, choose the one that best describes the two Statements. Statement-1: In Young's double slit experiment, the number of fringes observed in the field of view is small with longer wavelength of light and is large with shorter wavelength of light. Statement-2: In the double slit experiment the fringe width depends directly on the wavelength of light.