An astronomical telescope has a large aperture to

Two lenses of focal lengths 20 cm and -40 cm are held in contact. If an object lies at infinity, image formed by the lens combination will be a

The characteristic feature of light which remains unaffected on refraction is

The air bubble inside water shine due to

How does the focal length of a convex lens changes if mono chromatic red light is used instead of violet light?

When a convex lens placed inside a transparent medium of refracting index greater than that of its own material

The deviation of a ray on passing through a prism is (μ-1)A FOR

A thin prism of 12° angle gives a deviation of 6°. The refracting index of a material of the prism

The radius of curvature of the convex surface of a plano-convex lens, whose focal length is 0.3m & the refractive index of material is 1.5 is

The magnifying power of an astronomical telescope in the normal adjustment position is 100. The distance between objective & the eyepiece is 101cm. What is the focal length of objective?

A tank is filled with water to a height of 12.5cm. The apparent depth of a needle lying at bottom of tank is measured by a microscope to be 9.4cm. What is the refractive index of water?

Two thin lenses with focal lengths of 20 cm and 25 cm are placed in contact. The effective power of the combination is:

Tara is experimenting with a glass prism in her science lab. She shines a beam of light through the prism and observes the different colors that emerge. She notices that the angle of deviation for the colors varies. Which color does she find has the greatest angle of deviation?

An astronomical refractive telescope has an objective of focal length 20 m and an eyepiece of focal length 2 cm. Then

An astronomical refractive telescope has an objective of focal length 20 m and an eyepiece of focal length 2 cm. Which one of the following is not possible?

A convex lens is dipped in a liquid whose refractive index is equal to the refractive index of the lens. Then its focal length will

Which of the following is not a property of light?

Two concave mirrors have the same focal length but the aperture of one is larger than that of the other. Which mirror forms the sharper image?

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:

A man stands in front of a mirror of special shape. He finds that his image has a very small head, a fat body, and legs of normal size. What can we say about the shapes of the three parts of the mirror?

The refractive indices (R.I.) of glass and water with respect to air are 3/2 and 4/3 respectively. The R.I. of glass w.r.t. to water is:

Which of the following colour of white light deviated most when passes through a prism?

Two lenses of focal lengths 20 cm and –40 cm are held in contact. The image of an object at infinity will be formed by the combination at

A convergent lens will become less convergent in :

Two beams of red and violet color are made to pass separately through a prism (angle of the prism is 60°). In the position of minimum deviation, the angle of refraction will be

When light is refracted into a medium,

A ray of light incident at an angle θ on a refracting face of a prism emerges from the other face normally. If the angle of the prism is 5° and the prism is made of a material of refractive index 1.5, the angle of incidence is

Digital movie projectors work on the principle of

Day and night settings for rearview mirrors uses

When a beam of light is incident on a plane mirror, it is found that a real image is formed. The incident beam must be

An object is placed symmetrically between two plane mirrors, inclined at an angle of 72°, then the total number of images observed is

A person 1.6 m tall is standing at the centre between two walls three metre high. What is the minimum size of a plane mirror fixed on the wall in front of him, if he is to see the full height of the wall behind him?

While capturing solar energy for commercial purposes we use

A convex mirror has a focal length f. A real object is placed at a distance f in front of it, from the pole. It produces an image at

An object placed in front of a concave mirror of focal length 0.15 m produces a virtual image, which is twice the size of the object. The position of the object with respect to the mirror is

When a light ray from a rarer medium is refracted into a denser medium, its

A glass lens is immersed in water. What will be the effect on the power of lens?

An astronomical telescope has a large aperture to:

Two lenses of focal lengths 20 cm and -40 cm are held in contact. If an object lies at infinity, image formed by the lens combination will be at

In the minimum deviation position, the refracted ray in the prism is

Due to refraction, the depth of an optically denser medium appears to be

A convergent lens made of crown glass has focal length 20cm in air. If it is immersed in a liquid of refractive index 1.60, its focal length will be

A man runs towards a mirror at a rate of 6 m/s if we assume the mirror to be at rest, the image will have velocity -

Refractive index of water is 5/3. A light source is placed in water at a depth of 4 m. Then what must be the maximum radius of disc placed on water surface so that the light of source can be stopped?

A short linear object of length b lies along the axis of a concave mirror of focal length f at a distance u from the pole of the mirror. The size of image is approximately equal to

A ray of light travels from the point A to B with a uniform speed. On its way, it is reflected by the surface XX'. The path followed by the ray to take least time is

A Convex mirror of focal length f produces an image magnified m times. The distance of the object from the mirror is

A Thin lens of focal length f and its aperture has diameter d. it forms an image of intensity 3. Now the central part of aperture upto diameter d/2 is blocked by an opaque paper. The focal length and image intensity would change to

When a light ray from a rarer medium is refracted into a denser medium, its

Which of the following is possible application of fibre optics?

Two transparent media A and B are separated by a plane boundary. The speed of light in medium A is 2.0 x 10^8 ms^-1 and in medium B is 2.5 x 10^8 ms^-1. The critical angle for which a ray of light going from A to B suffers total internal reflection is

An object is placed at a distance of f/2 from a convex lens. The image will be

A glass concave lens is placed in a liquid in which it behaves like a convergent lens. The refractive index of glass is

The radii of curvatures of each of the surfaces of a convex lens (refractive index of the material is 1.5) is 20 cm. The focal length of the lens in air is

A glass lens is immersed in water. Its power will

A thin equiconvex glass lens of refractive index 1.5 has power of 5D. When the lens is immersed in a liquid of refractive index μ, it acts as a divergent lens of focal length 100 cm. The value of μ of liquid is _______.

At the minimum deviation of condition in a prism

Focal length of the objective and eyepiece of a telescope are respectively 50 cm and 5 cm. The magnifying power of the telescope in its normal adjustment is

The equivalent focal length of a combination of a convex and a concave length is

Two convex lenses are separated by a distance equal to the sum of their focal lengths. A beam of light parallel to the principal axis incidence on one of the lenses. They will emerge from the second lens as

When a telescope is adjusted for normal vision, the distance of the objective from the eye-piece is found to be 80 cm. The magnifying power of the telescope is 19. What are the focal lengths of the lenses?

While measuring refractive index of glass using a glass slab of thickness 3 cm and a travelling microscope a student observes that he needed to shift the microscope by 1 cm to refocus the mark on the base of the travelling microscope when the slab is kept on it. The refractive index of the material of the glass slab is

Total internal reflection occurs when

Objects are visible in light due to:

Even in absolutely clear water, a diver cannot see very clearly:

A lens behaves as a converging lens in air and as a diverging lens in water. The refractive index of the material is:

When a thin convex lens is put in contact with a thin concave lens of the same focal length, the resultant combination had focal length equal to:

A concave lens of focal length f produces an image 1/μ times the size of the object. The distance of the object from the lens is:

When length of a microscope tube increases, its magnifying power:

A microscope has an objective of 5mm focal length and eye piece of 30 mm focal length and the distance between them is 150 mm. The magnification is:

The magnifying power of an astronomical telescope can be increased if we:

Two convex lenses of focal lengths 0.3 m and 0.05 m are used to make a telescope. The distance kept between them is equal to:

When a ray of light goes from a rarer medium into a denser medium, then:

A ray of light can suffer total internal reflection when it goes from:

If refractive indices for water and glass are 4/3 and 5/3 respectively and light is tending to go from glass to water, the critical angle is:

Optical fibres use the phenomenon of:

In a glass prism:

The angle of minimum deviation for a hollow prism filled with a liquid is 30 degree. A ray of light falling on the prism is refracted at 30 degree. The refractive index of the liquid is:

In an experiment for determination of refractive index of glass of a prism by i-δ plot, it was found that a ray incident at angle 35°, suffers deviation of 40° and that it emerges an angle 79°. In that case which of the following is closest to the maximum possible value of refractive index?

An object 2.4m in front of a lens form a sharp image on a film 12 cm behind the lens. A glass plate 1 cm thick, of refractive index 1.50 is interposed between lens and film with its plane faces parallel to film. At what distance (from lens) should object shifted to be in sharp focus on film?

A green light is incident from the water to the air-water interface at the critical angle (θ). Select the correct statement

The focal length of plano-convex lens, the convex surface of which is slivered is .3m, if μ of the lens is 7/4, the radius of curvature of the convex surface is

The magnification of a compound microscope is 30 and the focal length of its eye piece is 5m. Calculate the magnification produced by the objective, when the image is to be formed at least distance of distinct vision (25 cm).

A convergent double of separated lens, corrected for spherical aberration, are separated by 2 m and has an equivalent focal length of 10 cm. Calculate the focal length of its component lenses.

Calculate the time taken by the light to travel a distance of $$500 m$$ in water of reflective index of $$\frac{4}{3}$$ . (Given the velocity of light in vacuum = $$3 \times 10^{10} cm/s$$ )

A telescope consist of two lenses of focal lengths 10 cm and 1 cm. Calculate the length of telescope, when an object is kept at distance of 60 cm from the objective, and the final image is formed is at least distance of distinct vision.

An equilateral prism deviates a ray through 45° for the two angle of incidence differing by 20°. The angle of incidence is

A compound microscope has an eyepiece of focal length 10 cm and an objective of focal length 4 cm. Calculate the magnification if an object is kept at a distance of 5 cm from the objective, then the final image is formed at the least distance of distinct vision.

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

Find the change in the focal length of the lens, if a convex lens of focal length 20 cm and refractive index 1.5, is emerged in water having refractive index 1.33.

Find the position of 1 cm tall object which is placed 8 cm in front of convex mirror of radius of curvature 24 cm.

If two mirrors are inclined at some angle an object is placed between the mirrors and there are seven images formed for an object. Then, what is an angle between the mirrors?

The shortest height of a vertical mirror required to see the entire image of a man will be

A beam of monochromatic blue light of wavelength 4200 Å in air travels in water (4 / 3). Its wavelength in water will be

A concave lens has a focal length of -10 cm. If an object is placed 15 cm from the lens, what is the position of the image formed?

What is the effect on the image distance when the object distance is decreased for a convex lens?

In a simple microscope, if the focal length of the convex lens is 5 cm, what is the maximum magnification achievable?

A person looks into a concave mirror and sees a larger image of themselves. What can we infer about the position of the object relative to the focal point of the mirror?