Refraction at Spherical Surfaces and by Lenses

Author:NCERT
12th CBSE
IMPORTANT

Important Questions on Refraction at Spherical Surfaces and by Lenses

MEDIUM
IMPORTANT

There are certain material developed in laboratories which have a negative refractive index (Figure). A ray incident from air (medium 1) into such a medium (medium 2) shall follow a path given by

EASY
IMPORTANT

The optical density of turpentine is higher than that of water while its mass density is lower. Figure given below shows a layer of turpentine floating over water in a container. For which one of the four rays incident on turpentine in figure, the path shown is correct?

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MEDIUM
IMPORTANT

The radius of curvature of the curved surface of a plano-convex lens is 20 cm. If the refractive index of the material of the lens be 1.5, it will

EASY
IMPORTANT

An object approaches a convergent lens from the left of the lens with a uniform speed 5 m/s and stops at the focus. The Image

EASY
IMPORTANT

A short pulse of white light is incident from air to a glass slab at normal incidence. After travelling through the slab, the first colour to emerge is

MEDIUM
IMPORTANT

An infinitely long cylinder of radius R is made of an unusual exotic material with refractive index –1 (Figure). The cylinder is placed between two planes whose normals are along the y direction. The centre of the cylinder O lies along the y-axis. A narrow laser beam is directed along the y direction from the lower plate. The laser source is at a horizontal distance x from the diameter in the y direction. Find the range of x such that light emitted from the lower plane does not reach the upper plane.


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HARD
IMPORTANT

If light passes near a massive object, the gravitational interaction causes a bending of the ray. This can be thought of as happening due to a change in the effective refractive index of the medium given by

nr=1+2 GM/rc2

where r is the distance of the point of consideration from the centre of the mass of the massive body, G is the universal gravitational constant, M the mass of the body and c the speed of light in vacuum. Considering a spherical object find the deviation of the ray from the original path as it grazes the object.
 

MEDIUM
IMPORTANT

The mixture of a pure liquid and a solution in a long vertical column (i.e, horizontal dimensions << vertical dimensions) produces diffusion of solute particles and hence a refractive index gradient along the vertical dimension. A ray of light entering the column at right angles to the vertical has deviated from its original path. Find the deviation in travelling a horizontal distance d<<h, the height of the column.

MEDIUM
IMPORTANT

Show that for a material with refractive index μ2 , light incident at any angle shall be guided along a length perpendicular to the incident face.

EASY
IMPORTANT

Three immiscible liquids of densities d1>d2>d3 and refractive indices μ1>μ2>μ3 are put in a beaker. The height of each liquid column is h3. A dot is made at the bottom of the beaker. For near normal vision, find the apparent depth of the dot.

EASY
IMPORTANT

An unsymmetrical double convex thin lens forms the image of a point object on its axis. Will the position of the image change if the lens is reversed?

EASY
IMPORTANT

A magnifying glass is used, as the object to be viewed can be brought closer to the eye than the normal near point. This results in

EASY
IMPORTANT

A rectangular block of glass ABCD has a refractive index 1.6. A pin is placed midway on the face AB (Figure). When observed from the face AD. the pin shall

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