Ray Optics

The frequency of a light wave in a material is 2 x 10¹⁴ Hz and wavelength is 5000 Å. The refractive index of material will be

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

A astronomical telescope has objective and eye-piece of focal lengths 40 cm, 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 45⁰. The angle of prism is 60⁰. If the ray suffers minimum deviation through the prism, then the angle of minimum deviation and refractive index of the material of the prism respectively, are

The near point and far point of a person are 40 cm and 250 cm, respectively. Determine the power of the lens he/she should use while reading a book kept at distance 25 cm from the eye.

Angle of minimum deviation for a prism of reractive index 1.5 equal to the angle of prism of given prism. Then, the angle of prism is …….
(sin 48⁰36′ =0.75)

A ray of light passes from a medium A having refractive index 1.6 to the medium B having refractive index 1.5. The value of critical angle of medium A is……..

The focal lengths of a converging lens are fᵥ and fᵣ for violet and red lights, respectively. Which of the following is correct?

The periodic waves of intensities I₁ and I₂ pass through a region at the same time in the same direction. The sum of the maximum and minimum intensities is:

A lens having focal length f and aperture of diameter d forms an image of intensity I. Aperture of diameter d/2 in central region of lens is covered by a black paper. Focal length of lens and intensity of image now will be respectively:

Dispersion of light is caused due to

Calculate the focal length of a reading glass of a person, if the distance of distinct vision is 75 cm

A person wants a real image of his own, 3 times enlarged. Where should he stand in front of a concave mirror of radius of curvature of 30 cm?

In Young’s double slit experiment the distance between the slits and the screen is doubled. The separation between the slits is reduces to half. As a result the fringe width

A parallel beam of light of wavelength λ is incident normally on a narrow slit. A diffraction pattern is formed on a screen placed perpendicular to the direction of the incident beam. At the second minimum of the diffraction pattern, the phase difference between the rays coming from the two edges of slit is

The limiting angle of incidence for an optical ray that can be transmitted by an equilateral prism of refractive index μ = √(7/3) is given by (angles can be assumed to be small, so that sine of the angle is angle itself)

A ray enters a glass sphere of refractive index μ=√3 at an angle of incidence of 60⁰, a ray is reflected and refracted at the farther surface of the sphere. The angle between the reflected and refracted rays at this surface is

To measure the roughness of the surface of a material, which of the following microscope is preferred for better result output?

To get three images of single object, one should have two plane mirrors at an angle of

An object placed at 20 cm in front of a concave mirror produces three times magnified real image. What is the focal length of the concave mirror?

In vacuum, to travel distance d, light takes time t and in medium to travel distance 5d, it takes time T. The critical angle of the medium is

The equiconvex lens has focal length f. If it is cut perpendicular to the principal axis passing through optical centre, then focal length of each half is

Two lenses of power 15 D and -3 D are placed in contact. The focal length of the combinations is

A luminous object is separated from a screen by distance d. A convex lens is placed between the object and the screen such that it forms a distinct image on the screen. The maximum possible focal length of this convex lens is

A focal length of a lens is 10 cm. What is power of a lens in dioptre?

Astigmatism is corrected by using

The intermediate image formed by the objective of a compound microscope is

An astronomical telescope arranged for normal adjustment has a magnification of 6. If the length of the telescope is 35 cm, then the focal lengths of objective and eye-piece respectively, are

Diameter of the objective of a telescope is 200 cm. What is the resolving power of a telescope? Take wavelength of light = 5000 Å.

Two thin lenses of focal lengths f₁ and f₂ are in contact and coaxial. The power of the combination is:

A boy is trying to start a fire by focusing sunlight on a piece of paper using an equiconvex lens of focal length 10 cm. The diameter of the sun is 1.39 x 10⁹ m and its mean distance from the earth is 1.5 x 10¹¹ m. What is the diameter of the Sun’s image on the paper?

For a normal eye, the cornea of eye provides a converging power 40 D and the least converging power of the eye lens behind the cornea is 20 D. Using this information, the distance between the retina and the cornea-eye lens can be estimated to be

A ray of light travelling in a transparent medium of refractive index µ, falls on surface separating the medium from air at an angle of incidence of 45⁰. For which of the following value of µ the ray can undergo total internal reflection?

An object is 8 cm high. It is desired to form a real image 4 cm high at 60 cm from the mirror. The type of mirror needed with the focal length is

Which one of the following is not due to total internal reflection?

When an object is placed 40 cm from a diverging lens, its virtual image is formed 20 cm from the lens. The focal length and power of lens are

A thin prism of angle 15⁰ made of glass of refractive index µ₁ = 1.5 is combined with another prism of glass of refractive index µ₂ = 1.75. The combination of the prism produces dispersion without deviation. The angle of the second prism should be

A person has a minimum distance of distinct vision as 50 cm. The power of lenses required to read a book at a distance of 25 cm is

The distance of the moon form the earth is 3.8 x 10⁵ km. Supposing that the eye is most sensitive to the light of wavelength 550 nm, the seperation of two points on the moon that can be resolved by a 500 cm telescope is

When a biconvex lens of glass having refractive index 1.47 is dipped in a liquid, it acts a plane sheet of glass. This implies that the liquid must have refractive index

A small angled prism of refractive index 1.4 is combined with another small angled prism of refractive index 1.6 to produce dispersion without deviation. If the angle of first prism is 6⁰, then the angle of the second prism is

The magnifying power of the astronomical telescope for normal adjustment is 50. The focal length of the eyepiece is 2 cm. The required length of the telescope for normal adjustment is

The magnifying power of a telescope is 9. When it is adjusted for parallel rays the distance between the objective and eyepiece is 20 cm. The focal length of lenses are:

Radii of curvature of a converging lens are in the ratio 1:2. Its focal length is 6 cm and refractive index is 1.5. Then, its radii of curvature are ………… respectively

The radius of curvature of the convex face of a plano-convex lens is 12 cm and the refractive index of the material of the lens is 1.5. Then, the focal length of the lens is

For the normal eye, the cornea of eye provides a converging power of 40 D and the least converging power of the eye lens behind the cornea is 20 D. Using this information, the distance between the retina and the eye lens of the eye can be estimated to be:

The reddish appearance of the sun at sunrise and sunset is due to

For having large magnification power of a compound microscope

The diameter of the eye ball of a normal eye is about 2.5 cm. The power of the eye lens varies from

A ray of light is incident at an angle of incidence i, on one face of a prism of angle A (assumed to be small) and emerges normally from the opposite face. If the refractive index of the prism is μ, then the angle of incidence i, is nearly equal to

A concave mirror of focal length f₁ is placed at a distance d from a convex lens of focal length f₂. A beam of light coming from infinity and falling on this convex lens concave mirror combination returns to infinity. The distance d must be equal

If the image formed by a convex mirror of focal length 30 cm is a quarter of the size of the object, then the distance of the object from the mirror will be

In a compound microscope, the focal length of the objective is 2.5 cm and of eye lens is 5 cm. If an object is placed at 3.75 cm before the objective and the image is formed at the least distance of distinct vision, then the distance between two lenses will be

A short linear object of length L lies on the axis of a spherical mirror of focal length f at a distance u form the mirror. Its image has an axial length L’ equal to

An object is placed at a distance of 10 cm from a co-axial combination of two lenses A and B in contact. The combination forms a real image three times the size of the object. If lens B is concave with a focal length of 30 cm. The nature and focal length of lens A is

The focal length of the objective of a terrestrial telescope is 80 cm and it is adjusted for parallel rays, then its power is 20. If the focal length of erecting lens is 20 cm, then full length of the telescope will be

The radius of curvature of a concave mirror is 24 cm and the image is magnified by 1.5 times. The object distance is