JEE Main Physics — Optics previous year questions with solutions.
In normal adjustment, for a refracting telescope, the distance between objective and eye piece is $30\mathrm{cm}$. The focal length of the objective, when the angular magnification of the telescope is $2$, will be:
In an experiment with a convex lens. The plot of the image distance $({v}^{'})$ against the object distance $({\mu }^{'})$ measured from the focus gives a curve ${v}^{'}{\mu }^{'}=225$. If all the distances are measured in $\mathrm{cm}$. The magnitude of the focal length of the lens is _____ $\mathrm{cm}$.
In a Young's double slit experiment, an angular width of the fringe is $0.35^{\circ}$ on a screen placed at $2m$ away for particular wavelength of $450\mathrm{nm}$. The angular width of the fringe, when whole system is immersed in a medium of refractive index $\frac{7}{5}$, is $\frac{1}{\alpha }$. The value of $\alpha$ is _____ .
In a Young's double slit experiment, a laser light of $560\mathrm{nm}$ produces an interference pattern with consecutive bright fringes' separation of $7.2\mathrm{mm}$. Now another light is used to produce an interference pattern with consecutive bright fringes' separation of $8.1\mathrm{mm}$. The wavelength of second light is _____ $\mathrm{nm}.$
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 $5\times {10}^{-2}m$ towards the slits, the change in fringe width is $3\times {10}^{-3}\mathrm{cm}$. If the distance between the slits is $1\mathrm{mm}$, then the wavelength of the light will be____$\mathrm{nm}$.
For an object placed at a distance $2.4m$ from a lens, a sharp focused image is observed on a screen placed at a distance $12\mathrm{cm}$ from the lens. A glass plate of refractive index $1.5$ and thickness $1\mathrm{cm}$ is introduced between lens and screen such that the glass plate plane faces parallel to the screen. By what distance should the object be shifted so that a sharp focused image is observed again on the screen?
Consider a light ray travelling in air is incident into a medium of refractive index $\sqrt{2n}$. The incident angle is twice that of refracting angle. Then, the angle of incidence will be
As shown in the figure, after passing through the medium $1$. The speed of light ${v}_{2}$ in medium $2$ will be : (Given $c=3\times {10}^{8}m{s}^{-1}$) 
An unpolarised light beam of intensity $2{I}_{0}$ 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
An object '$O$' is placed at a distance of $100\mathrm{cm}$ in front of a concave mirror of radius of curvature $200\mathrm{cm}$ as shown in the figure. The object starts moving towards the mirror at a speed $2\mathrm{cm}{s}^{-1}$. The position of the image from the mirror after $10s$ will be at _____ $\mathrm{cm}$. 
A wave of frequency $=3\mathrm{GHz}$, strikes a particle of size ${(\frac{1}{100})}^{th}$ of $\lambda$, then this phenomenon is called as
A thin prism of angle $6^{\circ}$ and refractive index for yellow light $({n}_{Y})1.5$ is combined with another prism of angle $5^{\circ}$ and ${n}_{Y}=1.55$. The combination produces no dispersion. The net average deviation $(\delta )$ produced by the combination is ${(\frac{1}{x})}^{^{\circ}}$. The value of $x$ is _____ . 
A small bulb is placed at the bottom of a tank containing water to a depth of $\sqrt{7}m$. The refractive index of water is $\frac{4}{3}$. The area of the surface of water through which light from the bulb can emerge out is $x\pi {m}^{2}$. The value of $x$ is _____ .
A ray of light is incident at an angle of incidence $60^{\circ}$ on the glass slab of refractive index $\sqrt{3}$. After refraction, the light ray emerges out from other parallel faces and lateral shift between incident ray and emergent ray is $4\sqrt{3}\mathrm{cm}$. The thickness of the glass slab is _____ $\mathrm{cm}$.
A parallel beam of light is allowed to fall on a transparent spherical globe of diameter $30\mathrm{cm}$ and refractive index $1.5$. The distance from the centre of the globe at which beam of light can converge is _____ $\mathrm{mm}$.
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 light wave travelling linearly in a medium of dielectric constant $4$, incidents on the horizontal interface separating medium with air. The angle of incidence for which the total intensity of incident wave will be reflected back into the same medium will be : (Given : relative permeability of medium ${\mu }_{r}=1$)
A light ray is incident, at an incident angle ${\theta }_{1}$, on the system of two plane mirrors ${M}_{1}$ and ${M}_{2}$ having an inclination angle $75^{\circ}$ between them (as shown in figure). After reflecting from mirror ${M}_{1}$ it gets reflected back by the mirror ${M}_{2}$ with an angle of reflection $30^{\circ}$. The total deviation of the ray will be _____ degree. 
A convex lens of focal length $20\mathrm{cm}$ is placed in front of convex mirror with principal axis coinciding each other. The distance between the lens and mirror is $10\mathrm{cm}$. A point object is placed on principal axis at a distance of $60\mathrm{cm}$ from the convex lens. The image formed by combination coincides the object itself. The focal length of the convex mirror is _____ $\mathrm{cm}$.
A convex lens has power $P$. It is cut into two halves along its principal axis. Further one piece (out of the two halves) is cut into two halves perpendicular to the principal axis (as shown in figures). Choose the incorrect option for the reported pieces. 
Your friend is having eye sight problem. She is not able to see clearly a distant uniform window mesh and it appears to her as nonuniform and distorted. The doctor diagnosed the problem as :
White light is passed through a double slit and interference is observed on a screen $1.5m$ away. The separation between the slits is $0.3\mathrm{mm}$. The first violet and red fringes are formed $2.0\mathrm{mm}$ and $3.5\mathrm{mm}$ away from the central white fringes. The difference in wavelengths of red and violet light is $(\text{in}\mathrm{nm}).$
Two satellites revolve around a planet in coplanar circular orbits in anticlockwise direction. Their period of revolutions are $1$ hour and $8$ hours respectively. The radius of the orbit of nearer satellite is $2\times {10}^{3}\mathrm{km}.$ The angular speed of the farther satellite as observed from the nearer satellite at the instant when both the satellites are closest is $\frac{\pi }{x}rad{h}^{-1}$, where $x$ is $_______.$
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 $\sqrt{5}=2.3$) 