JEE Main Physics — Optics previous year questions with solutions.
A convex lens (of focal length $20 cm$ ) and a concave mirror, having their principal axes along the same lines, are kept $80 cm$ apart from each other. The concave mirror is to the right of the convex lens. When an object is kept at a distance of $30 cm$ to the left of the convex lens, its image remains at the same position even if the concave mirror is removed. The maximum distance of the object for which this concave mirror, by itself would produce a virtual image would be:
Consider a Young's double slit experiment as shown in figure. What should be the slit separation $d$ in terms of wavelength $\lambda$ such that the first minima occurs directly in front of the slit $({S}_{1})$ ? 
Two coherent sources produce waves of different intensities which interfere. After interference, the ratio of the maximum intensity to the minimum intensity is $16.$ The intensity of the waves are in the ratio:
A transparent cube of side $d$, made of a material of refractive index ${\mu }_{2}$, is immersed in a liquid of refractive index ${\mu }_{1}({\mu }_{1}<{\mu }_{2})$. A ray is incident on the face $AB$ at an angle $\theta$ (shown in the figure). Total internal reflection takes place at the point $E$ on the face $BC.$  Then, $\theta$ must satisfy
In a Young's double slit experiment, the path difference, at a certain point on the screen, betwen two interfering waves is $\frac{1}{8}$ th of wavelength. The ratio of the intensity at this point to that at the centre of a bright fringe is close to:
A plano - convex lens (focal length ${f}_{2}$ , refractive index ${\mu }_{2},$ radius of curvature R) fits exactly into a plano - concave lens (focal length ${f}_{1},$ refractive index ${\mu }_{1},$ radius of curvature R). Their plane surfaces are parallel to each other. Then, the focal length of the combination will be:
A plano-convex lens of refractive index ${\mu }_{1}$ and focal length ${f}_{1}$ is kept in contact with another plano-concave lens of refractive index ${\mu }_{2}$ and focal length ${f}_{2}.$ If the radius of curvature of their spherical faces is $R$ each and ${f}_{1}=2{f}_{2},$ the ${\mu }_{1}$ and ${\mu }_{2}$ are related as:
In a young's double slit experiment, the slits are placed $0.320 mm$ apart. Light of wavelength $\lambda =500 nm$ is incident on the slits. The total number of bright fringes that are observed in the angular range $-{30}^{o}\leq \theta \leq {30}^{o}$ is:
A concave mirror has radius of curvature of $40 cm.$ It is at the bottom of a glass that has water filled up to $5 cm$ (see figure). If a small particle is floating on the surface of water, its image as seen, from directly above the glass, is at a distance $d$ from the surface of water. The value of $d$ is close to: (Refractive index of water $=1.33)$ 
One plano-convex and one plano-concave lens of the same radius of curvature $R$ but of different materials are joined side by side as shown in the figure. If the refractive index of the material of $1$ is ${\mu }_{1}$ and that of $2$ is${ \mu }_{2}$, then the focal length of the combination is: 
A concave mirror for face viewing has a focal length of $0.4 m$. The distance at which you hold the mirror from your face in order to see your image upright with a magnification of $5$ is
An object is at a distance of $20 \mathrm{~m}$ from a convex lens of focal length $0.3 \mathrm{~m}$. The lens forms an image of the object. If the object moves away from the lens at a speed of $5 \mathrm{~m} / \mathrm{s}$ the speed and direction of the image will be
In a double slit experiment, when a thin film of thickness $t$ having refractive index $\mu$ is introuduced in front of one of the slits, the maximum at the centre of the fringe pattern shifts by one fringe width. The value of $t$ is $(\lambda$ is the wavelength of the light used):
A point source of light, S is placed at a distance L in front of the center of plane mirror of width d which is hanging vertically on a wall. A man walks in front of the mirror along a line parallel to the mirror, at a distance 2L as shown below. The distance over which the man can see the image of the light source in the mirror is: 
A monochromatic light is incident at a certain angle on an equilateral triangular prism and suffers minimum deviation. If the refractive index of the material of the prism is $\sqrt{3}$, then the angle of incidence is :
In a Young's double-slit experiment, the ratio of the slit's width is $4 :1$ . The ratio of the intensity of maxima to minima, close to the central fringe on the screen, will be
A light wave is incident normally on a glass slab of refractive index $1.5.$ If $4%$ of light gets reflected and the amplitude of the electric field of the incident light is $30\frac{V}{m},$ then the amplitude of the electric field for the wave propagating in the glass medium will be:
The graph shows how the magnification $m$ produced by a thin lens varies with image distance $v$. The focal length of the lens used is 
In figure, the optical fiber is $l=2 m$ long and has a diameter of $d=20 \mu m.$ If a ray of light is incident on one end of the fiber at angle ${\theta }_{1}=40^{\circ}$ , the number of reflections it makes before emerging from the other end is close to: (refractive index of fiber is $1.31$ , $sin 40^{\circ}=0.64$ and ${\mathrm{sin}}^{-1}0.49=30^{\circ}$ .) 
Unpolarized light of intensity $I$ is incident on a system of two polarizers, $A$ followed by $B$. The intensity of emergent light is $\frac{I}{2}$ . If a third the polarizer $C$ is placed between $A$ and $B$ the intensity of emergent light is reduced to $\frac{I}{3}$ . The angle between the polarizers $A$ and $C$ is $\theta$ , then
A plano-convex lens becomes an optical system of $28\mathrm{cm}$ focal length when its plane surface is silvered and illuminated from left to right as shown in fig$-A$ If the same lens is instead silvered on the curved surface and illuminated from another side as in fig-$B$, it acts as an optical system of focal length $10\mathrm{cm}$. The refractive index of the material of the lens is: 
A convergent doublet of separated lenses, corrected for spherical aberration, has resultant focal length of $10 \mathrm{~cm}$. The separation between the two lenses is $2 \mathrm{~cm}$. The focal lengths of the component lenses
A particle is oscillating on the $\mathrm{X}$-axis with an amplitude $2 \mathrm{~cm}$ about the point $x_0=10 \mathrm{~cm}$ with a frequency $\omega$. A concave mirror of focal length 5 $\mathrm{cm}$ is placed at the origin (see figure) Identify the correct statements: (A) The image executes periodic motion (B) The image executes non-periodic motion (C) The turning points of the image are asymmetric w.r.t the image of the point at $x$ $=10 \mathrm{~cm}$ (D) The distance between the turning points of the oscillation of the image is $\frac{100}{21}$ 
A particle is oscillating on the $x$-axis with an amplitude $2\mathrm{cm}$ about the point ${x}_{0}=10 \mathrm{cm}$ with a frequency. A concave mirror of focal length $5\mathrm{cm}$ is placed at the origin (see figure).  Identify the correct statements? (i) The image executes periodic motion. (ii) The image executes non-periodic motion. (iii) The turning points of the image are asymmetric with respect to the image of the point at $X=10 \mathrm{cm}$. (iv) The distance between the turning points of the oscillation of the image is $\frac{100}{21} \mathrm{cm}$.