Recent questions tagged class12

A system of lens consists of two convex lenses of focal length $f_1= 30\;cm$ and $f_2 =20\;cm$. Separated by a distance 'd'. When a parallel beam of light is incident on the first lens after two refraction the resultant rays come out parallel then the distance 'd' is

asked Jan 22, 2014 by meena.p

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A convex lens of focal length 20 cm is placed glass slab of refractive index $\large\frac{3}{2}$.A parallel beam of light is incident on the convex lens. The light will converge.

asked Jan 22, 2014 by meena.p

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In an young double slit experiment the slit separation is 3 times the wave length of the light used What is the maximum number of interference maxima possible

asked Jan 22, 2014 by meena.p

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Two light waves whose equation are given respectively as $y_1 = 6\sin wt; y_2 =8 \sin (wt+ 8)$ super impose to form a interference pattern. The ratio of maximum to minimum intensities of the super imposed wave is

asked Jan 21, 2014 by meena.p

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A man can view through telescope two district objects at a distance of $120 \;m$ from him if he uses light of $ \lambda= 550 A^{\circ}$ What must be minimum separation between objects if diameter of his pupil $D= 2.5 \;mm$

asked Jan 21, 2014 by meena.p

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Parallel beam of monochromatic light of wavelength $\lambda =4800 \mathring{A}$ is incident on a single slit of size $0.2 mm$ . The angular divergence in which most of light is diffracted is [ie between two 1st order maxima on both sides]

asked Jan 21, 2014 by meena.p

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In Fresnel bi prism experiment if prism angle $\alpha=1^{\circ}, \mu=1.54$ distance between prism and sources a is $0.3\;m$ and wave length $ \lambda= 180 \pi \;nm$ find the fringe width, distance between screen and prism $b= 0.7 \;m$

asked Jan 21, 2014 by meena.p

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In a young's double slit experiment two films of same thickness 't' but of different refractive indices $\mu_1$ and $\mu_2$ are placed in front of slit A and B respectively. If $( \mu_1 > \mu_2)$ the central maxima will

asked Jan 21, 2014 by meena.p

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An interference pattern is obtained by using red light. If in the same set up red light is replaced by blue light the fringe width will

asked Jan 21, 2014 by meena.p

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A young's double slit experiment uses light of wavelength $900\; nm$ A plate of thickness 't' of material of refractive index $\mu=1.5$ i placed in front of one of the slits. What should be the thickness of plate 't' so that the central fringe becomes dark.

asked Jan 21, 2014 by meena.p

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As a result of interference of two coherent source of light , the energy is :

asked Jan 21, 2014 by meena.p

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Two light sources emit light of same wavelength $\lambda$. They will form interfering patterns if

asked Jan 21, 2014 by meena.p

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If a light beam is incident at polarising angle, $(55.3^{\circ})$ on glass air interface , What is angle of refraction in glass?

asked Jan 21, 2014 by meena.p

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What is dispersive power of glass if $\mu_v =1.522$ and $\mu_r =1.514$

asked Jan 21, 2014 by meena.p

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Two glass prisms of refractive index $1.5$ and $ 1.6$ are kept in contact and a ray of light is incident on this combination of prism. The light emerges out of this combination un deviation The angle of prism of refractive index $1.6 $ is $5^{\circ}$ What is angle of prism of the other prism.

asked Jan 21, 2014 by meena.p

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Speed of light is maximum in

asked Jan 21, 2014 by meena.p

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Focal length of eye piece of a compound microscope is

asked Jan 21, 2014 by meena.p

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What is maximum magnification that can be obtained from a convex lens of focal length 5 cm. (the least distance vision is 25 cm)

asked Jan 21, 2014 by meena.p

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A man is advised to wear lens as he can see objects between 15 cm and 30 cm. If he uses lens to see far off objects what will be his near point.

asked Jan 21, 2014 by meena.p

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In a Young's double slit experiment set up the 10th maxima is 3 cm from the central maxima . If the whole set up is immersed in a liquid of refractive index $\mu=1.5$ What will be the new fring width

asked Jan 21, 2014 by meena.p

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In same Young's Double slit experiment set up two sources of light produces fringes of width $0.2 \;mm$ and $0.3 \;mm$ The ratio of wave length of two light sources is

asked Jan 21, 2014 by meena.p

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Monochromatic light from narrow slits produce a interference pattern of fridge width $\beta$ , for a certain slit separation. When the slit separation is doubled and distance between screen and slit distance between screen and slit is made $\large\frac{1}{3}$ rd the fringe width

asked Jan 21, 2014 by meena.p

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In a Young's double slit experiment separation between two consecutive dark. fringes is $1.2 \;mm$, wave length $\lambda$ of light is $600 \;nm$ Distance between source and screen $D= 1 m $, the separation between slits is

asked Jan 21, 2014 by meena.p

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Two coherent sources hence intensities in the ratio $81 : 4$. The ratio $I_{max} \;and\; I_{min}$ of the interfering light is

asked Jan 20, 2014 by meena.p

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A doubled convex lens of refractive index $\mu$ is kept inside two immiscible liquids of refractive inclines $\mu_1$ and $\mu_2$. as shown $\mu_2 < \mu < \mu _1$ , A parallel beam of light is incident on the lens. After refraction on the lens we will get,

asked Jan 20, 2014 by meena.p

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A person carrying a plane mirror facing his back is moving with a speed of V m/s. Another person is following the mirror at the speed of u m/s. What is the speed of approach of the person to the image in the mirrors.

asked Jan 20, 2014 by meena.p

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A lens made of material of refractive index $\mu =\large\frac{3}{2} $ when placed in air behaves as shown in figure (1) . But when placed in a medium of refractive index $\mu_s$ it behaves as shown in figure (2) . Then the value of $\mu_s $ is

asked Jan 20, 2014 by meena.p

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A ray of light strikes a material of refractive index $\mu= \sqrt 3$. If the reflected and refracted light are perpendicular to each other, what is the angle of incidence.

asked Jan 20, 2014 by meena.p

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A luminous point is kept inside tank of water at a depth of 10 m below the surface. $\mu$ for water is $\large\frac{4}{3}$ . What must be the minimum diameter of card placed on the surface of water so that it cuts off all the light coming out.

asked Jan 20, 2014 by meena.p

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Plane surface of plane - convex lens is silvered and it then acts like a concave mirror of focal length . 30 cm. If the refractive index of the lens is 1.5 , the radius of curvature of convex surface is

asked Jan 20, 2014 by meena.p

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A point object is placed at the centre of a glass sphere of radius 6 and refractive index 1.5 . The distance of the virtual image from the surface of the sphere is

asked Jan 20, 2014 by meena.p

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White light is incident on the surface of glass and air as shown. Green light just grazes the surface. then the emergent ray in air contains

asked Jan 20, 2014 by meena.p

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Two plane mirrors A and B are alligned parallel to each other as shown. A ray of light is incident at an angle $30^{\circ}$ at a point just inside on one end of mirror A. What is the maximum number of reflection the ray undergoes before it emerges out.

asked Jan 20, 2014 by meena.p

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For a concave mirror as u (object distance ) varies v (the image distance ) also varies. The graph between $\large\frac{1}{u}$ and $\large\frac{1}{v}$

asked Jan 20, 2014 by meena.p

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Let ray of light given by the vector $ \overrightarrow{A}= 6 \sqrt 3 \hat i+8 \sqrt 3 \hat j -10 \hat k $ be incident on the $X-Y$ plane . Which is the boundary between two transparent medium. Medium 1 in $ Z > 0$ has refractive index of $\sqrt 2$ and medium 2 with $Z > 0$ has refractive index of $\sqrt 3 $. What is the angle of refraction in medium 2.

asked Jan 20, 2014 by meena.p

1 answer

A lens of focal $30\; cm$ and diameter 5 cm forms an image of intensity I. If central part of the lens is covered by black circular paper of diameter $2.5 \;cm$ What will be the new focal length and new intensity of image.

asked Jan 20, 2014 by meena.p

1 answer

Given the following statement: Some pins are clips. Some clips are pens. Now, consider the claims: C1 :Some pins are pens and C2: No pin is a pen. Now, mark according to the rules - \[\] i) Mark A if C1 is true, ii) Mark B if C2 is true,iii) Mark C if neither C1 nor C2 is true and iv) Mark D if both C1 and C2 are true.

asked Jan 18, 2014 by balaji.thirumalai

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An erect image is seen of $\large\frac{1}{5} $ th the height of the object kept at a distance of $20 \;cm$ from a mirror. The mirror must be :

asked Jan 17, 2014 by meena.p

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Two mirrors an inclined to each other at an angle $\theta$ It produces 5 images for a given object . Then,

asked Jan 17, 2014 by meena.p

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What should be the focal length of a simple magnifying lens so that it magnifies 10 times and the image is formed 25 cm from the eye.

asked Jan 17, 2014 by meena.p

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Light enters a triangular at an incident angle of $\theta$ at the point Q with an angle of refraction equal to $90^{\circ}$ , What is the refractive index of prism in terms of $\theta$ . The angle of the prism is $90^{\circ}$

asked Jan 17, 2014 by meena.p

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The figure shows graph between incident angle and refracted angle for two cases. case 1: when light travels from material 1 to air and case 2: when light travels from material 2 to air. The refractive index of material 1 and material 2 are

asked Jan 17, 2014 by meena.p

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Ostwald's process is a chemical process for making nitric acid $\text{HNO}_3$ by which of the following methods:

asked Jan 17, 2014 by sreemathi.v

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The figure shows total internal reflection taking place in three materials of refractive indices $n_1,n_2$ and $n_3$ where $\theta _{\large c_1},\theta _{\large c_2},\theta _{\large c_3}$ are critical angles in the respective mediums. Then

asked Jan 17, 2014 by meena.p

1 answer

A mirror of width 'l' m is kept on a wall. A person is approaching the mirror from the front. An observer is behind a screen has a view of the mirror as shown. How far from the mirror will be person be when the observer will be able to see him in the mirror.

asked Jan 17, 2014 by meena.p

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A transparent solid rod in the shape of a cuboid has refractive index $\sqrt 3$ The cuboid is kept in air, light enters midpoint (0) of one end of rod as shown . What should be the incident angle $\theta$ Such that when the refracted ray grazes along the wall.

asked Jan 17, 2014 by meena.p

1 answer

Bottom of a water tank is silvered A point object (dust particle) is at P inside the liquid at a height of 2 m from the base. An observer seeing directly from above sees both the image and the object What is the apparent distance between the object and image $(\mu_0 =\large\frac{4}{3} ) $

asked Jan 17, 2014 by meena.p

1 answer

Two mirror one concave of radius of curvature $0.4\;m$ and another convex mirror of radius of curvature $0.2 \;m$ are kept facing each other which are $0.5\;m$ apart. An object is placed between two mirrors, $0.25\;m$ from concave mirror. Where is the image formed after two reflections.

asked Jan 17, 2014 by meena.p

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A convex lens of focal length 40 cm is kept in contact with a concave lens of focal length 25 cm. What is power of this combined lens system.

asked Jan 17, 2014 by meena.p

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A light enters a transparent glass slab of refractive index $\mu=\large\frac{3}{2} $. The reflected ray and refracted ray are mutually perpendicular, The angle of incidence is

asked Jan 17, 2014 by meena.p

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