Geometrical Optics

The lens combination as shown in the figure, consists of two lenses, $L_1$ and $L_2$, of the focal lengths +10 cm and -10 cm , respectively. The position of the image formed is:

Which of the following measurements require 'index correction'?

Consider three media $P, Q$ and $R$ with refractive indices $1,1.25$, and 1.5 respectively. The medium $Q$ having a thickness of 5 cm is placed between extended media $P$ and $R$ as shown in the figure. An object $O$ is placed at the centre...

A ray of monochromatic light is passing through an equilateral prism $(A B C)$ as shown in the figure. The refracted ray $(Q R)$ is parallel to its base $(B C)$ and the angle of incidence $(i)$ is $50^{\circ}$. Then the angle of deviation $...

In a concave lens, a ray of light emanating from the object parallel to the principal axis of the lens after refraction:

A microscope has an objective of focal length 2 cm , eyepiece of focal length 4 cm and the tube length of 40 cm . If the distance of distinct vision of eye is 25 cm , the magnification in the microscope is

In a certain camera, a combination of four similar thin convex lenses are arranged axially in contact. Then the power of the combination and the total magnification in comparison to the power ( $p$ ) and magnification ( $m$ ) for each lens ...

Given below are two statements:
Statement I : Image formation needs regular reflection and/or refraction.
Statement II : The variety in colour of objects we see around us is due to the constituent colours of the light incident on them.
In t...

A light ray enters through a right angled prism at point \(P\) with the angle of incidence \(30^{\circ}\) as shown in figure. It travels through the prism parallel to its base \(B C\) and emerges along the face \(A C\). The refractive index...

A small telescope has an objective of focal length \(140 \mathrm{~cm}\) and an eye piece of focal length \(5.0 \mathrm{~cm}\). The magnifying power of telescope for viewing a distant object is:

An object is mounted on a wall. Its image of equal size is to be obtained on a parallel wall with the help of a convex lens placed between these walls. The lens is kept at distance x in front of the second wall. The required focal length of...

A horizontal ray of light is incident on the right angled prism with prism angle \(6^{\circ}\). If the refractive index of the material of the prism is 1.5 , then the angle of emergence will be:

\(\epsilon_0\) and \(\mu_0\) are the electric permittivity and magnetic permeability of free space respectively. If the corresponding quantities of a medium are \(2 ~\epsilon_0\) and \(1.5 ~\mu_0\) respectively, the refractive index of the ...

A lens is made up of 3 different transparent media as shown in figure. A point object O is placed on its axis beyond \(2f\). How many real images will be obtained on the other side?

Two thin lenses are of same focal lengths \((f)\), but one is convex and the other one is concave. When they are placed in contact with each other, the equivalent focal length of the combination will be :

In the figure shown here, what is the equivalent focal length of the combination of lenses (Assume that all layers are thin) ?

Light travels a distance \(\mathrm{x}\) in time \(t_{1}\) in air and \(10 \mathrm{x}\) in time \(t_{2}\) in another denser medium. What is the critical angle for this medium?

An astronomical refracting telescope is being used by an observer to observe planets in normal adjustment. The focal lengths of the objective and eye piece used in the construction of the telescope are 20 m and 2 cm respectively. Consider t...

During a cloudy day, a primary and a secondary rainbow may be created, then the :

Two transparent media A and B are separated by a plane boundary. The speed of light in those media are 1.5 \(\times\) 108 m/s and 2.0 \(\times\) 108 m/s, respectively. The critical angle for a ray of light for these two media is

A light ray falls on a glass surface of refractive index \(\sqrt3\), at an angle 60\(^\circ\). The angle between the refracted and reflected rays would be

A biconvex lens has radii of curvature, 20 cm each. If the refractive index of the material of the lens is 1.5, the power of the lens is

A point object is placed at a distance of 60 cm from a convex lens of focal length 30 cm. If a plane mirror were put perpendicular to the principal axis of the lens and at a distance of 40 cm from it, the final image would be formed at a di...

A lens of large focal length and large aperture is best suited as an objective of an astronomical telescope since :

A convex lens 'A' of focal length 20 cm and a concave lens 'B' of focal length 5 cm are kept along the same axis with a distance 'd' between them. If a parallel beam of light falling on 'A' leaves 'B' as a parallel beam, then the distance '...

Find the value of the angle of emergence from the prism. Refractive index of the glass is \(\sqrt 3\)

The Brewster's angle ib for an interface should be :

A ray is incident at an angle of incidence i on one surface of a small angle prism (with angle of prism A) and emerges normally from the opposite surface. If the refractive index of the material of the prism is \(\mu\), then the angle of i...

In total internal reflection when the angle of incidence is equal to the critical angle for the pair of media in contact, what will be angle of refraction?

Pick the wrong answer in the context with rainbow.

Two similar thin equi-convex lenses, of focal length f each, are kept coaxially in contact with each other such that the focal length of the combination is F1. When the space between the two lenses is filled with glycerin (which has the sam...

An object is placed at a distance of 40 cm
from a concave mirror of focal length 15 cm.
If the object is displaced through a distance
of 20 cm towards the mirror, the displacement
of the image will be

An astronomical refracting telescope will have
large angular magnification and high angular
resolution, when it has an objective lens of

The refractive index of the material of a prism
is \(\sqrt 2\) and the angle of the prism is 30°. One
of the two refracting surfaces of the prism is
made a mirror inwards, by silver coating. A
beam of monochromatic light entering the
prism...

A thin prism having refracting angle 10o is made of glass of refractive infex 1.42. This prism is combined with another thin prism of glass of refractive index 1.7. This combination producess dispersion without deviation. The refracting ang...

A beam of light from a source L is incident normally on a plane mirror fixed at a certain distance x from the source. The beam is reflected back as a spot on a scale placed just above the source L. When the mirror is rotated through a small...

A person can see clearly objects only when they lie between 50 cm and 400 cm from his eyes . In order to increase the maximum distance of distinct vision to infinity, the type and power of the correcting lens, the person has to use. will be

An air bubble in a glass slab with refractive index 1.5 (near normal incidence) is 5 cm deep when viewed from one surface and 3 cm deep when viewed from the opposite face. The thickness (in cm) of the slab is

Two identical glass (\(\mu\)g = 3/2) equiconvex lenses of focal length \(f\) each are kept in contact. The space between the two lenses is filled with water \(\left( {{\mu _w} = 4/3} \right)\). The focal length of the combination is

A astronomical telescope has objective and eyepiece of focal lengths 40 cm and 4 cm respectively. To view an object 200 cm away from the objective, the lenses must be separated by a distance

The angle of incidence for a ray of light at a refracting surface of a prism is 45o. The angle of prism is 60o. If the ray suffers minimum deviation through the prism, the angle of minimum deviation and refractive index of the material of ...

Match the corresponding entries of column 1 with column 2. [Where m is the magnification produced by the mirror]

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The refracting angle of a prism is A, and refractive index of the material of the prism is cot (A/2). The angle of minimum deviation is

Two identical thin plano-convex glass lenses (refractive index 1.5) each having radius of curvature of 20 cm are placed with their convex surfaces in contact at the centre. The intervening space is filled with oil of refractive index 1.7. T...

A beam of light consisting of red, green and blue colours is incifent on a right angled prism. The refractive index of the material of the prism for the above red, green and blue wavelengths are 1.39, 1.44 and 1.47 respectively.

The pris...

In an astronomical telescope in normal adjustment a straight black line of length L is drawn on inside part of objective lens. The eye-piece forms a real image of this line. The length of this image is \(I\). The magnification of the telesc...

The angle of a prism is A. One of its refracting surfaces is silvered. Light rays falling at an angle of incidence 2 A on the first surface returns back through the same path after suffering reflection at the silvered surface.
The refracti...

If the focal length of objective lens is increased then magnifying power of

Two plane mirrors are inclined at 70o. A ray incident on one mirror at angle, \(\theta\) after reflection falls on second mirror and is reflected from there parallel to first mirror. The value of \(\theta\) is

A plano convex lens fits exactly into a plano concave lens. Their plane surfaces are parallel to each other. If lenses are made of different materials of refractive indices \(\mu\)1 and \(\mu\)2 and R is the radius of curvature of the cur...