  Types Of Questions

## Ray Optics And Optical Instruments

- Wondering what kind of questions that can be asked in next exam? Here you go!
1
Single Correct
An object starts moving at an angle at with the principal axis as shown in fig in front of a biconvex lens of focal length . If denotes the angle at which image starts to move with principal axis, then:
A
B
C
D
Two identical glass rods and (refractive index = 1.5) have one convex end of radius of curvature They are placed with the curved surfaces at a distance as shown in the figure, with their axes (shown by the dashed line) aligned. When a point source of light is placed inside rod on its axis at a distance of from the curved face, the light rays emanating from it are found to be parallel to the axis inside The distance is:
A
B
C
D
A light ray is incident on a plane mirror . The mirror is rotated in the direction as shown in the figure by an arrow at frequency . The light reflected by the mirror is received on the wall at a distance from the axis of rotation. When the angle of incidence becomes the speed of the spot (a point) on the wall is:
A
B
C
D
None of these
2
Multiple Correct
A ray of light is incident normally on one face of a prism as shown in figure. The refractive index of the material of the prism is  and the prism is immersed in water of refractive index  then
This question has multiple correct options
A
The angle of emergence of the ray is
B
The angle of emergence of the ray is
C
The angle of emergence of the ray is
D
Total internal reflection will not occur at P if the refractive index of water increases to a value greater than by dissolving some substance
Consider an optical system placed in water PQRS is a hollow glass slab filled with air This slab is kept on the principle axis of a lens in such a way that surface PS makes an angle with the axis of the lens. , then
This question has multiple correct options
A
for transmission of light takes place through slab sin
B
for transmission of light through slab sin
C
for cm final image is at 3m distance from O
D
for cm final image is at 3m distance from O
Two parallel rays are incident on a thin lens of refractive index 1.5 as shown in figure and radius of curvature of its surfaces are 30 cm & 60 cm . Origin of coordinate axes is at the optical centre of the lens.Then
This question has multiple correct options
A
focal length of lens is 120 cm
B
light rays get reflected (TIR) from first surface of the lens
C
y-coordinate of the point at which light rays focus is -4 cm
D
y-coordinate of the point at which light rays focus is 4 cm
3
Numerical Type I
A thin biconvex lens of refractive index and radius of curvature is placed on a reflecting convex surface of radius of curvature . A point object is placed on the principal axis of the system such that its final image coincides with itself. Now, few drops of a transparent liquid is placed between the mirror and lens such that final image of the object is at infinity. Find refractive index of the liquid used. Also, find the position of the object.
A thin biconvex lens of refractive index is placed on a horizontal plane mirror as shown. The space between the lens and the mirror is then filled with water of refractive index . It is found that when a point object is placed above the lens on its principal axis, the object coincides with its own images. On representing with another liquid, the object and the image again coincide at a distance from the lens. Calculate , if the refractive index of the liquid is
AB and CD are two slabs. The medium between the slabs has refractive index 2. Find the minimum angle of incidence (in degrees) at Q so that the ray is totally reflected by both the slabs.
4
Numerical Type II
A composite slab consisting of different media is placed in front of concave mirror of radius of curvature as shown in Fig. The whole arrangement is immersed in water. Locate the final image of point object .
A particle is moving at a constant speed from a large distance towards concave mirror of radius along the principal axis. If the speed of the images as a function of the distance of the particle from the mirror is given as . Find
A cylindrical glass rod has its two coaxial ends of spherical from bulging outward. The front and has a radius of curvature and the back end which is silvered has a radius of curvature . The thickness of the rod along the axis is . Calculate the position of the image of a point at the axis from front face
5
Matrix Match Type I
An object (real) is placed at focus of an equi-biconvex lens as shown in Fig. The refractive index of the lens is and the radius of curvature of either surface of lens is . The lens is surrounded by air. In each statement of column I, some changes are made to situation given above and information regarding final image formed as a result is given in Column II. The distance between lens and object is unchanged in all statements of column I. Match the statements in column I with resulting image in column II.
List 1If the refractive index of the lens is doubled (that is, made ,) thenIf the radius of curvature is doubled (that is, made 2R,) thenIf a glass slab of refractive between the object and lens as shown, thenIf the left side of lens is filled with a medium of refractive index as shown, then  List 2Final image is realFinal image is virtualFinal image becomes smaller in size in comparison to size of image before the change was madeFinal image is of same size as the object
6
Matrix Match Type II
For a prism of refracting angle A and refractive index 2. Assume rays are incident at all angles of incidence . Ignore partial reflection
List 1
List 2All rays are reflected back from the second surfaceAll rays are refracted into air from the second faceSome rays are reflected back from second surfaceSome rays are refracted into air from the second surface
Two transparent media of refractive indices and have a solid lens shaped transparent material of refractive index between them as shown in figures in Column II. A ray traversing these media is also shown in the figures. In Column I different relationship between and are given. Match them to the ray diagram shown in Column II.
List 1
List 2     7
Passage Type
For two structure namely with and with and and taking the refractive index of water to be and that of air to be , the correct option(s) is (are)
A
of immersed in water is the same as that of immersed in a liquid of refractive index
B
of immersed in liquid of refractive index is the same as that of immersed in water
C
of placed in air is the same as that of immersed in liquid of refractive index
D
of placed in air is the same as that of laced in water
The amplitude of oscillation of the image is
A
B
C
D
image does not oscillate