Why does a ray of light passing through the centre of curvature of a concave mirror gets reflected along same path after reflection?

What kind of image is formed on a cinema screen?

What do you mean by laterally inverted?

The image formed by a convex mirror is observed to be virtual, erect and extremely diminished than the object, what should be the position of the object?

Which type of spherical mirror has a larger field of view?

A spherical mirror has focal length -10 cm. What type of mirror is it likely to be?

If the magnification of an image formed by a mirror is positive, what does it mean?

What is the magnification produced by a rear view mirror fitted in vehicles?

Rays from the sun converge at a point 15 cm in front of a concave mirror. Where an object should be placed, so that its image formed is equal to the size of the object?

An object is placed at a distance of 8 cm form a convex mirror of focal length 12 cm. Find the position of the image formed?

If the object distance for a concave mirror is 24 cm and image distance is 12 cm in front of a mirror. Then, find the magnification of the mirror.

The depth of a bucket filled with water seems to be less than its actual depth. Name the phenomenon responsible for this?

A light ray is incident on a rectangular glass slab at an angle of 60°. What is the angle between the ray coming out of the slab and the normal to the face of rectangular slab from which it comes out?

How is the refractive index of a medium related to the speed of light? Give an expression for refractive index of a medium with respect to another in terms of speed of light in these two media?

For the same angle of incidence, the angle of refraction in three different media A, B and C 10°, 25° and 40°, respectively. In which medium the velocity of light will be maximum?

Calculate the angle of incidence of light ray incident of surface of a plastic slab of refractive index √3, if the angle of refraction is 30°.

If a ray of light enters from alcohol to air. The refractive index of alcohol is 1.36. Calculate the speed of light in alcohol with respect to air.

The refractive index of glass with respect to air is and refractive index of water with respect to air is . What will be the refractive index of water with respect to glass?

Name the lens which always forms a virtual image of an object.

Discuss the case when a convex lens forms a virtual and enlarged image.

Which lens would you prefer to use while reading small letters from a dictionary?

What type of lens is an air bubble inside the water?

A convex lens of focal length 20 cm can produce a magnified virtual as well as real image. Is this a correct statement? If yes, where shall the object be placed in each case for obtaining these images?

A convex lens of focal length 20 cm can produce a magnified virtual as well as real image. Is this a correct statement? If yes, where shall the object be placed in each case for obtaining these images?

A student uses a lens of focal length- 50 cm. What is the nature of the lens and its power?

You are provided with two lenses of focal length 20 cm and 30 cm, respectively. Which lens will you use to obtain more convergent light?

A lens has power 4 D. Find the focal length that lens.

Two lenses of power -3.5 D and + 1 D are placed in contact. Find the total power of the combination of lens. Calculate the focal length of this combination.

If two lenses (convex) are in contact with each other, what happens to the ray after refraction?

A lens is cut into two equal halves

(i) along the principal axis

(ii) Perpendicular to principal axis. What will be the focal length of each half?

What is the radius of curvature of a plane mirror?

What is the power of sun glasses?

What is the value of speed of light in free space?

For what position of an object, a concave mirror forms a real image equal in size to the object?

Does the value of speed of light change with medium?

A concave mirror forms sharp image of a distant tree. What is the separation between the mirror and the screen called?

Does refractive index change with color of light?

Magnification produced by a concave mirror of a body 4.0 cm in size is 0.16 what is the size of image?

Redraw the ray diagram given below in your answer book and completer the path of ray.

The refractive index of water is 1.33 and the speed of light in air 3 × 10⁸ ms^–1. Calculate the speed of light in water.

Draw a ray diagram to show the path of the reflected ray corresponding to an incident ray of light parallel to the principal axis of a convex mirror and show the angle of incidence and angle of reflection on it.

How do we say a medium to be rarer or denser? Give two reasons.

When we focus sunlight using a convex lens at the tip of a matchstick, what will happen? Why?

A dentist uses a mirror in front of a decayed tooth at a distance of 4 cm from the tooth to get four times magnified image in the mirror. Use mirror formula to find the focal length and nature of the mirror used.

A ray of light strikes the glass slab at an angle of 90°. What are the angle of incidence and the angle of refraction?

When two or more lenses are placed in contact, what will be their combined power?

A ray of light incident on one face of a rectangular glass slab emerges from the opposite face of the slab parallel to the direction of the incident ray. Why does it happen so?

A ray passing through the centre of curvature of a spherical mirror after reflection returns along the same path. Why?

Why does a ray of light bend from its path when it travels from one medium to other?

A ray of light traveling from a medium x enters obliquely into another medium Y. If it bends away from the normal, then state which one of the two is relatively optically denser. Why?

Why is the refractive index of atmosphere different at different altitudes?

For the same angle of incidence in medium P, Q and R, the angles refraction are , and respectively. In which medium will the velocity of light be minimum? Give reason for your answer.

What is meant by refractive index? If the speed of light in a medium is 2/3rd of the speed of light in vacuum, find the refractive index of that medium.

The radius of curvature of a concave mirror is 50 cm. Where should an object be placed in the mirror, so as to form its image at infinity? Justify your answer.

Draw the ray diagram in your answer book and show the formation of image of object AB with suitable rays. Mention the position and nature of image.

How far should an object be placed from a convex lens of focal length 20 cm to obtain its image at a distance of 30 cm from the lens? What will be the height of the image, if the objects is 6 cm tall?

An object of size 7.0 cm is placed at a distance of 27 cm in front of concave mirror of focal length 18 cm. At what distance from the mirror should a screen be placed so that a sharply focused image can be obtained? Find the size and the nature of the image.

A 5.0 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 20 cm. The distance of the object from the lens is 30 cm By calculation determine

(i) the position and

(ii) the size of the image formed.

An object placed 45 cm from a lens forms an image on a screen place 90 cm on the other side of the lens. Identify the type of the lens and find its focal length.

Does the incident and emergent ray coincide in the process of refraction through glass slab? Give reason.

A ray of light enters a diamond from air. If the refractive index of diamond is 2.42, what % (percentage) is speed of light in diamond with that of speed in air?

The image of an object place at 60 cm in front of a lens is obtained on a screen at a distance of 120 cm from it. Find the focal length of the lens. What would be the lens? What would be the height of the image? If the object is 5 cm high?

Two lenses have power of (a) + 2D (b) – 4D. What is the nature and focal length of each lens?

An object is kept at a distance of 100 cm from each of the above lenses.

Calculate the

(a) image distance and

(b) magnification in each of two cases.

List the sign conventions for reflection of light by spherical mirror. Draw a diagram and apply these conventions in the determination of focal length of a spherical mirror which forms three times magnified real image of an object placed. 16 cm in front of it.

List the new Cartesian sign convention for reflection of light by spherical mirrors. Draw a diagram and apply these conventions for calculating the focal length and nature of a spherical mirror which forms 1/3 times magnified virtual image of an object placed 18 cm if front of it.

State and define the SI unit of power of a lens.

A convex lens of focal length 25 cm and a concave lens of focal length 10 cm are placed in close contact with each other. Calculate the lens power of this combination.

List the sign conventions that are followed in case of refraction of light through spherical lenses. Draw a diagram and apply these conventions in determining the nature and focal length of a spherical lens which forms three times magnified real image of an object placed 16 cm from the lens.

State the laws of refraction of light. Write an expression to relate absolute refractive index of a medium with speed of light in vacuum.

The refractive index of a medium x with respect to y is 2/3 and the refractive index of medium y with respect to z is 4/3 Calculate the refractive index of medium z with respect to medium x

Varun’s mom is finding it difficult to cook in the kitchen as there was power cut and she was complaining about it to Varun. He immediately took a plane mirror from his shelf made it stand against a wall such that sun’s rays were focused into the kitchen directly on the cook top, due to the reflection of the mirror. There was some light now and his mother was able to finish her work.

(i) What are the characteristic of the image formed by a plane mirror?

(ii) What values did Varun display?

Mr. Raghav, grade 6 teacher find that his students do not draw when he draws on the board. Every time he had to turn towards them to see whether they draw and label the diagrams. Arav, one of his student fixed two big convex mirrors at the two sides of the black board. With this Mr. Raghav was able to draw and also supervise his students through the mirror. All the students started doing their work property.

(i) Which characteristics of convex lens, let Mr. Raghav to do both his job at the same time?

(ii) What value did Arav and Mr. Raghav show?

A virtual image three times the size of the object is obtained with a concave mirror of radius of curvature 36 cm. The distance of the object from the mirror is 

A convex mirror of focal length f forms an image of the size of the object. The distance of the object from the mirror is

A perfecting reflecting mirror has an area of 1cm². Light energy is allowed to fall on it for an hour at the rate of 10 Wcm-2. The force that acts on the mirror is

An object is placed at the centre of curvature of a concave mirror. The distance between its image and the pole is

The refractive index of lens flint glass is 1.65 and for alcohol, it is 1.36 with respect to air, then the refractive index of the dens flint glass with respect to alcohol is

Refractive index of diamond with respect to glass is 1.6. If the absolute refractive index of glass is 1.5, then the absolute refractive index of diamond is

A ray of light from a denser medium strikes a rarer medium at an angle incidence as shown in figure. The reflected and refracted rays make an angle of 90 with each other. The angles of reflection and refraction and r and r1. The critical angle is

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 d in cm will be

A thick plane-convex lens made of crown glass (refractive index 1.5) has thickness of 3 cm at its centre. The radius of curvature of the spherical surface is 5 cm.

An link mark made at the centre of its plane face, when viewed normal through the curved face, appears to be at a distance x from the curved face. Then, x is equal to

An object is placed in front of a screen and a convex lens is placed at a position such that the size of the image formed is 9cm. when the lens is shifted through a distance of 20 cm, the size of the image becomes 1 cm. The focal length of the lens and the size of the object are respectively.