Ray Optics Test...

At Kavalur in India, astronomers using a telescope whose objective had a diameter of 1 m started using a telescope of diameter 2.54 m. This resulted in

A lens of focal length 50 cm forms an image of a distant object, which subtends an angle of 1 milliradian at the lens. What is the size of the image?

A telescope has an objective of focal length 200 cm and an eyepiece of focal length 5 cm. What is the magnification of the telescope?

The principal section of a glass prism is an isosceles triangle ABC with AB = AC. One face AC of the glass prism is silvered as shown in the figure. If a ray is incident normally on the face AB and after two reflections, it emerges from the base BC perpendicular to it, what is the measure of angle BAC?

Each quarter of a vessel of depth 'H' is filled with liquids of refractive indices n₁, n₂, n₃ and n₄ from the bottom. The apparent depth of the vessel, when observed normally, is

Material A has a critical angle i_A and material B has a critical angle i_B (i_B > i_A).

Which of the following statements are true?

(i) Light can be totally internally reflected when it passes from B to A.
(ii) Light can be totally internally reflected when it passes from A to B.
(iii) The critical angle for total internal reflection is i_B - i_A.
(iv) The critical angle between A and B is ^.

A pIano-convex lens acts like a concave mirror of 28 cm focal length when its plane surface is silvered and like a concave mirror of 10 cm focal length when its curved surface is silvered. What is the refractive index of the material of the lens?

If a ray of light in a denser medium enters into a rarer medium at an angle of incidence i, the angles of reflection and refraction are r and r', respectively. If the reflected and refracted rays are at right angle to each other, then the critical angle for the given pair of media is

In the visible region, the dispersive powers and the mean angular deviations for crown and flint glass prisms are and , and d and d', respectively. When the two prisms are combined, the condition of zero dispersion of the combination is

A ray of light passes from vacuum into a medium of refractive index , and the angle of incidence is found to be twice the angle of refraction. Then, angle of incidence is

A ray of light passes through an equilateral prism such that an angle of incidence is equal to the angle of emergence, and the latter is equal to th the angle of prism. The angle of deviation is

Directions: For the given statements of assertion and reason, mark the correct answer as follows:

(a) If both assertion and reason are true and reason is the correct explanation of assertion.
(b) If both assertion and reason are true, but reason is not the correct explanation of assertion.
(c) If assertion is true, but reason is false.
(d) If both assertion and reason are false.

Assertion: A biconvex lens of focal length 10 cm is split into two equal parts by a plane parallel to its principal axis. The focal length of each part will be 20 cm.
Reason: Focal length does not depend on radii of curvature of two surfaces.

The refractive index of glass with respect to a medium is 4/3. If the difference between the velocities of light in medium and in glass is 6.25 x 10⁷ m/s, then what is the velocity of light in the medium?

A bird in air looks at a fish vertically below it inside water. X is height of the bird above the surface of water, and Y is depth of the fish below the surface of water. If the refractive index of water with respect to air is , the distance of the fish as observed by the bird is

A given ray of light suffers minimum deviation in an equilateral prism P. Additional prisms Q and R of identical shape and material are now added to P (as shown in the figure). The ray will suffer

A thin prism P₁ with angle 4° made from a glass of refractive index 1.54 is combined with another thin prism P₂ made from glass of refractive index 1.72 to produce dispersion without deviation. The angle of the prism P₂ is

One of the refracting surfaces of a prism of refractive indexis silvered. The angle of the prism is equal to critical angle of a medium of refractive index 2. A ray of light incident on the unsilvered surface passes through the prism and retraces its path after reflection at the silvered face. Then, the angle of incidence on the unsilvered surface is

A small telescope has an objective lens of focal length 144 cm and an eyepiece of focal length 6.0 cm. What is the magnifying power of the telescope and the separation between the objective lens and the eyepiece?

A microscope is focused on a mark on a piece of paper. A slab of glass of thickness 3 cm and refractive index 1.5 is placed over the mark. How should the microscope be moved to get the mark in focus again?

A ray of light is incident normally on one face of a right-angled isosceles prism. Then, it grazes the hypotenuse. The refractive index of material of the prism is

A light ray is travelling between two media as given below. The angle of incidence on the boundary in all the cases is 30^o. Identify the correct sequence of increasing order of angles of refraction.

(1) Air to water
(2) Water to glass
(3) Glass to water
(Refractive indices of glass and water are and , respectively.)

What is the time taken by sunlight to pass through a window of thickness 4 mm, whose refractive index is ?

White light is incident on one of the refracting surfaces of a prism of angle 5°_^. If refracting indices for red and blue colours are 1.659 and 1.641, respectively, then the angular dispersion between these two colours, when they emerge out of the prism, is

A prism of refractive index has a refracting angle of 60^o. At what angle must a ray be incident on it so that it suffers a minimum deviation?

If light travels distance 'x' in 't₁' seconds in air and distance '10x' in 't_2^' seconds in another medium, then what will be the critical angle of that medium?