Recent questions in Physics

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

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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

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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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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

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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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A thin prism of angle $8^{\circ}$ produces a deviation of $4 ^{\circ} [\delta =4^{\circ}]$ What is the refractive index of the material of the prism.

asked Jan 17, 2014 by meena.p

1 answer

The wave length of light in 1st liquid is $2500 \;\mathring{A}$, and that in 2nd liquid is $5000\; \mathring{A}$, What is the critical angle of 1st liquid with respect to 2nd liquid.

asked Jan 17, 2014 by meena.p

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A swimmer is swimming at a depth of 12 m below the surface. A bird flying in the sky appears 36 m directly above his eyes. At what height is the bird is actually flying from the surface of water

asked Jan 16, 2014 by meena.p

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Refractive index for a piece of transparent material is greatest for

asked Jan 16, 2014 by meena.p

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An object is placed in front of a concave mirror of focal length f. A virtual image of magnification 2 is formed.How for must the object be moved from original position so that a real image of same size is formed.

asked Jan 16, 2014 by meena.p

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A right angled prism ABC is dipped in water . such that the surface AB is in air as shown. A ray of light is normally. What must be the possible value of $\theta$ so that the say gets totally reflected at AC to reach surface BC.

asked Jan 16, 2014 by meena.p

1 answer

A ray of light is incident on side of a right angled prism normally. It then falls on the hypotenuse of the prism and gets reflected back as shown. If $\theta=45^{\circ}$ then the refractive index of the material of prism is

asked Jan 16, 2014 by meena.p

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A ray of light travelling in glass enters glass water interface at an angle $\theta$. It finally emerges into air parallel to the surface of water. $ \mu_w=\large\frac{4}{3}$. What is the refractive index of glass.

asked Jan 16, 2014 by meena.p

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A combination of lens is formed by keeping two identical equiconvex lens of focal length f kept in contact and the space between them filled with liquid of refractive index $\mu_2 =\large\frac{4}{3}$. Focal length of the combination is

asked Jan 16, 2014 by meena.p

1 answer

A ray of light is incident on glass sphere of refractive index $\large\frac{3}{2}$. The ray incident at two surfaces after travelling through the sphere emerges tangential to the surface of the sphere. What must be the incident angle.

asked Jan 16, 2014 by meena.p

1 answer

A small point object is inside a glass surface as shown. Refraction takes place at concave spherical boundry separating glass air medium. For the image to be real the object distance u is (R-Radius of curvature of the surface , $\mu of glass =\large\frac{3}{2}$ )

asked Jan 16, 2014 by meena.p

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Position of object (u) reflected from concave varies from $0$ to $\infty$ which of the graph represents the variation of object distance (v) with respect to (u)

asked Jan 16, 2014 by meena.p

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A glass slab of refractive index $1.5$ and thickness $3\;cm$ is placed on a black dot on a piece of paper. A person looks at the mark from a height of $8\; cm $ above it. The dot will appear at a distance.

asked Jan 16, 2014 by meena.p

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A ray of light is incident from air on a surface of medium at an angle of $60^{\circ}$. The angle of refraction in the medium is $ 30^{\circ}$ what will be the velocity of light in the medium.

asked Jan 16, 2014 by meena.p

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A ray of light is incident on a rectangular glass block at $45^{\circ}$ on glass- air interface. The refractive index of glass is $\sqrt 2$. Then

asked Jan 16, 2014 by meena.p

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light travels through a glass of refractive index $\mu =1.5 $ of thickness $4 mm$. What is the time taken for the light to cross it

asked Jan 16, 2014 by meena.p

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A light wave has wavelength $6000 \mathring{A}$ in vacuum. The wavelength of this light when it passes through a certain glass of refraction index $(\mu =1.5 ) $ is

asked Jan 16, 2014 by meena.p

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Wavelength of a colour of light for air is $6000\;\mathring{A}$ and in water the wavelength is $4500\;\mathring{A}$. What is the speed of light in water.

asked Jan 16, 2014 by meena.p

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Image formed by a concave mirror of is three times of the object Focal length of the mirror is 6 cm. Then the object distance is

asked Jan 16, 2014 by meena.p

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