Optics PYQ — Page 12

A ray of light entering from air into a denser medium of refractive index $\frac{4}{3}$, as shown in figure. The light ray suffers total internal reflection at the adjacent surface as shown. The maximum value of angle $\theta$ should be equal to: 

The focal length of a convex lens is 10 cm. Its power is:

A convex lens of focal length 20 cm forms an image...

An object is placed at a distance of $12\mathrm{cm}$ from a convex lens. A convex mirror of focal length $15\mathrm{cm}$ is placed on another side of the lens at $8\mathrm{cm}$ as shown in the figure. The image of the object coincides with the object.  When the convex mirror is removed, a real and inverted image is formed at a position. The distance of the image from the object will be $___\mathrm{cm}$

Car $B$ overtakes another car $A$ at a relative speed of $40{ms}^{-1}$. How fast will the image of car $B$ appear to move in the mirror of focal length $10\mathrm{cm}$ fitted in car $A$, when the car $B$ is $1.9m$ away from the car $A$?

A ray of laser of a wavelength $630\mathrm{nm}$ is incident at an angle of $30^{\circ}$ at the diamond-air interface. It is going from diamond to air. The refractive index of diamond is $2.42$ and that of air is $1$. Choose the correct option.

Find the distance of the image from object $O,$ formed by the combination of lenses in the figure: 

Two plane mirrors ${M}_{1}$ and ${M}_{2}$ are at right angle to each other shown. A point source $P$ is placed at $a$ and $2a$ meter away from ${M}_{1}$ and ${M}_{2}$ respectively. The shortest distance between the images thus formed is : (Take $\sqrt{5}=2.3$) 

In the Young's double slit experiment, the distance between the slits varies in time as $d(t)={d}_{0}+{a}_{0}\mathrm{sin}\omega t$; 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 coherent light sources having intensity in the ratio $2x$ produce an interference pattern. The ratio $\frac{{I}_{\mathrm{max}}-{I}_{\mathrm{min}}}{{I}_{\mathrm{max}}+{I}_{\mathrm{min}}}$ will be

The thickness at the centre of a plano convex lens is $3\mathrm{mm}$ and the diameter is $6\mathrm{cm}.$ If the speed of light in the material of the lens is $2\times {10}^{8}{ms}^{-1}.$ The focal length of the lens is ___________.

A prism of refractive index $\mu$ and angle of prism $A$ is placed in the position of minimum angle of deviation. If minimum angle of deviation is also $A$, then in terms of refractive,

A deviation of $2^{\circ}$ is produced in the yellow ray when prism of crown and flint glass are achromatically combined. Taking dispersive powers of crown and flint glass are $0.02$ and $0.03$ respectively and refractive index for yellow light for these glasses are $1.5$ and $1.6$ respectively. The refracting angles for crown glass prism will be ________$^{\circ}$ (in degree) (Round off to the Nearest Integer)

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

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

The image of an object placed in air formed by a convex refracting surface is at a distance of $10m$ behind the surface. The image is real and is at $\frac{{2}^{rd}}{3}$ of the distance of the object from the surface. The wavelength of light inside the surface is $\frac{2}{3}$ times the wavelength in air. The radius of the curved surface is $\frac{x}{13}m$, the value of $x$ is ______ .

A ray of light passing through a prism $(\mu =\sqrt{3})$ suffers minimum deviation. It is found that the angle of incidence is double the angle of refraction within the prism. Then, the angle of prism is (in degrees).

Given below are two statements : one is labeled as Assertion $A$ and the other is labeled as Reason $R$. Assertion $A$: For a simple microscope, the angular size of the object equals the angular size of the image. Reason $R$: Magnification is achieved as the small object can be kept much closer to the eye than $25\mathrm{cm}$ and hence it subtends a large angle. In the light of the above statements, choose the most appropriate answer from the options given below:

The focal length $f$ is related to the radius of curvature $r$ of the spherical convex mirror by:

A prism of refractive index ${n}_{1}$ and another prism of refractive index ${n}_{2}$ are stuck together (as shown in the figure). ${n}_{1}$ and ${n}_{2}$ depend on $\lambda ,$ the wavelength of light, according to the relation ${n}_{1}=1.2+\frac{10.8\times {10}^{-14}}{{\lambda }^{2}}$ and ${n}_{2}=1.45+\frac{1.8\times {10}^{-14}}{{\lambda }^{2}}$ The wavelength for which rays incident at any angle on the interface $BC$ pass through without bending at that interface will be ____ $\mathrm{nm}.$ 

Cross-section view of a prism is the equilateral triangle $ABC$ shown in the figure. The minimum deviation is observed using this prism when the angle of incidence is equal to the prism angle. The time taken by light to travel from $P$ (midpoint of $BC$) to $A$ is ___________ $\times {10}^{-10}s.$ (Given, speed of light in vacuum $=3\times {10}^{8}m{s}^{-1}$ and $\mathrm{cos}30^{\circ}=\frac{\sqrt{3}}{2}$) 

Three rays of light, namely red $(R)$, green $(G)$ and blue $(B)$ are incident on the face $PQ$ of a right angled prism $PQR$ as shown in figure.  The refractive indices of the material of the prism for red, green and blue wavelength are $1.27,1.42$ and $1.49$ respectively. The colour of the ray(s) emerging out of the face $PR$ is :

Consider the diffraction pattern obtained from the sunlight incident on a pinhole of diameter $0.1\mu m.$ If the diameter of the pinhole is slightly increased, it will affect the diffraction pattern such that

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 direction, the intensity of emerging light will be _______Lumens.