Optics PYQ — Page 6

The width of one of the two slits in Young's double slit experiment is d while that of the other slit is $x \mathrm{~d}$. If the ratio of the maximum to the minimum intensity in the interference pattern on the screen is $9: 4$ then what is the value of $x$ ? (Assume that the field strength varies according to the slit width.)

Light emerges out of a convex lens when a source of light kept at its focus. The shape of wavefront of the light is :

If the distance between object and its two times magnified virtual image produced by a curved mirror is $15\mathrm{cm}$, the focal length of the mirror must be :

A parallel beam of monochromatic light of wavelength $5000\overset{o}{A}$ is incident normally on a single narrow slit of width $0.001\mathrm{mm}$. The light is focused by convex lens on screen, placed on its focal plane. The first minima will be formed for the angle of diffraction of ______ (degree).

Light from a point source in air falls on a convex curved surface of radius $20\mathrm{cm}$ and refractive index $1.5$. If the source is located at $100\mathrm{cm}$ from the convex surface, the image will be formed at ______ $\mathrm{cm}$ from the object.

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

A parallel beam of monochromatic light of wavelength $600 \mathrm{~nm}$ passes through single slit of $0.4 \mathrm{~mm}$ width. Angular divergence corresponding to second order minima would be ______ $\times 10^{-3} \mathrm{rad}$.

The thin lens formula is:

The critical angle for total internal reflection from a medium to air is 30°...

If the refractive index of the material of a prism is $\mathrm{cot}(\frac{A}{2})$, where $A$ is the angle of prism then the angle of minimum deviation will be

A convex lens of focal length $40\mathrm{cm}$ forms an image of an extended source of light on a photoelectric cell. A current $I$ is produced. The lens is replaced by another convex lens having the same diameter but focal length $20\mathrm{cm}$. The photoelectric current now is

An effective power of a combination of 5 identical convex lenses which are kept in contact along the principal axis is $25 \mathrm{D}$. Focal length of each of the convex lens is :

A beam of unpolarised light of intensity ${I}_{0}$ 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 :

In Young's double slit experiment, light from two identical sources are superimposing on a screen. The path difference between the two lights reaching at a point on the screen is $\frac{7\lambda }{4}$. The ratio of intensity of fringe at this point with respect to the maximum intensity of the fringe is:

In a single slit experiment, a parallel beam of green light of wavelength $550 \mathrm{~nm}$ passes through a slit of width $0.20 \mathrm{~mm}$. The transmitted light is collected on a screen $100 \mathrm{~cm}$ away. The distance of first order minima from the central maximum will be $x \times 10^{-5} \mathrm{~m}$. The value of $x$ is :

The following figure represents two biconvex lenses $L_1$ and $L_2$ having focal length $10 \mathrm{~cm}$ and $15 \mathrm{~cm}$ respectively. The distance between $L_1 \& L_2$ is : 

A biconvex lens of refractive index $1.5$ has a focal length of $20\mathrm{cm}$ in air. Its focal length when immersed in a liquid of refractive index $1.6$ will be:

Given below are two statements : Statement I : When the white light passed through a prism, the red light bends lesser than yellow and violet. Statement II : The refractive indices are different for different wavelengths in dispersive medium. In the light of the above statements, chose the correct answer from the options given below:

The refractive index of a prism with apex angle $A$ is $cot\frac{A}{2}$. The angle of minimum deviation is :

The refractive index of prism is $\mu=\sqrt{3}$ and the ratio of the angle of minimum deviation to the angle of prism is one. The value of angle of prism is _______.

A microwave of wavelength $2.0\mathrm{cm}$ falls normally on a slit of width $4.0\mathrm{cm}.$ The angular spread of the central maxima of the diffraction pattern obtained on a screen $1.5m$ away from the slit, will be:

A convex mirror of radius of curvature $30\mathrm{cm}$ forms an image that is half the size of the object. The object distance is :

The width of one of the two slits in a Young's double slit experiment is 4 times that of the other slit. The ratio of the maximum of the minimum intensity in the interference pattern is:

The distance between object and its two times magnified real image as produced by a convex lens is $45\mathrm{cm}$. The focal length of the lens used is ________$\mathrm{cm}$.