Light – Reflection and Refraction

The magnification “ m “ for a mirror is +1 what does this signify ?

If refractive index of glass is 1.65, What is the speed of light in glass. ?

What is absolute refractive index ?

What will happen to a ray of light when it falls normally on a surface ?

Which phenomenon occurs when light falls on(a) highly polished surface (b) a transparent medium ?

Find the power of a concave lens of focal length 2m.

An object 1cm high produces a real image 1.5 cm high, when placed at a distance

of 15 cm from concave mirror. Calculate the position of the image.

An object 1cm high produces a real image 1.5 cm high, when placed at a distance

Write two uses of concave mirror.

An object is placed at a distance of 50cm from a convex mirror. State two characteristics of the image formed.

Focal length of a convex mirror is 10cm.Find the radius of curvature of themirror?

The power of a lens is -2D. Is the lens convex or concave?

An image formed in a spherical mirror has magnification -2.Is the image real or virtual?

When a ray of light passes from a denser medium to a rarer medium which angle is greater: angle of incidence or angle of refraction?

The size of an object is 2cm.The magnification produced by a mirror is +1. What is the size of the image?

Define one dioptre?

Which mirror is used as rear view mirror in vehicles and why ?

Name the lens which always gives an erect and diminished image?

Which of the two has a great power? A lens of short focal length or a lens of large focal length?

Name the point inside the lens through which a ray of light goes undeviated?

What does negative sign in the value of magnification of a mirror indicate?

What will happen to ray of light when it travels from rarer medium to a denser medium ?

A ray of light is incident on a concave mirror along its principal axis. What will be the angle of reflection?

A person uses concave mirror for shaving, where should he position his face in front of it ?

Where is the image formed in a convex mirror, when the object is anywhere in front of it ?

A doctor has prescribed a corrective lens of power +1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging?

Find the focal length of a lens of power -2.0 D. What type of lens is this?

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

 An object 5.0 cm in length is placed at a distance of 20 cm in front of a convex mirror of radius of curvature 30 cm. Find the position of the image, its nature and size.

The magnification produced by a plane mirror is +1. What does this mean?

 An object is placed at a distance of 10 cm from aconvex mirror of focal length 15 cm. Find the position and nature of the image.

 A concave lens of focal length 15 cm forms an image 10 cm from the lens. How far is the object placed from the lens? Draw the ray diagram.

An object 5 cm in length is held 25 cm away from a converging lens of focal length 10 cm. Draw the ray diagram and find the position, size and the nature of the image formed.

One-half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object? Verify your answer experimentally. Explain your observations.

Name the type of mirror used in the following situations.

(a) Headlights of a car

(b) Side/rear-view mirror of a vehicle

(c) Solar furnace

Support your answer with reason.

We wish to obtain an erect image of an object, using a concave mirror of focal length 15 cm. What should be the range of distance of the object from the mirror? What is the nature of the image? Is the image larger or smaller than the object? Draw a ray diagram to show the image formation in this case.

No matter how far you stand from a mirror, your image appears erect. The mirror is likely to be

(a) plane

(b) concave

(c) convex

(d) either plane or convex

No matter how far you stand from a mirror, your image appears erect. The mirror is likely to be

(a) plane

(b) concave

(c) convex

(d) either plane or convex

A spherical mirror and a thin spherical lens have each a focal length of -15 cm. The mirror and the lens are likely to be

(a) both concave

(b) both convex

(c) the mirror is concave and the lens is convex

(d) the mirror is convex, but the lens is concave

Where should an object be placed in front of a convex lens to get a real image of the size of the object?

(a) At the principal focus of the lens

(b) At twice the focal length

(c) At infinity

(d) Between the optical centre of the lens and its principal focus.

The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should be the position of the object?

(a) Between the principal focus and the centre of curvature

(b) At the centre of curvature

(c) Beyond the centre of curvature

(d) Between the pole of the mirror and its principal focus.

Which one of the following materials cannot be used to make a lens?

(a) Water

(b) Glass

(c) Plastic

(d) Clay

Find the power of a concave lens of focal length 2 m.

A convex lens forms a real and inverted image of a needle at a distance of 50 cm from it. Where is the needle placed in front of the convex lens if the image is equal to the size of the object? Also, find the power of the lens.

Define 1 dioptre of power of a lens.

The refractive index of diamond is 2.42. What is the meaning of this statement?

You are given kerosene, turpentine and water. In which of these does the light travel fastest? Use the information given in Table.

find out, from Table, the medium having highest optical density. Also find the medium with lowest optical density.

 Light enters from air to glass having refractive index 1.50. What is the speed of light in the glass? The speed of light in vacuum is 3 x 10

Aray of light travelling in air enters obliquely into water. Does the light ray bend towards the normal or away from the normal? Why?

 A concave mirror produces three times magnified (enlarged) real image of object placed at 10 cm in front of it. Where is the image located?

Find the focal length of a convex mirror whose radius of curvature is 32 cm.

Why do we prefer a convex mirror as a rear-view mirror in vehicles?

Name the mirror that can give an erect and enlarged image of an object.

The radius of curvature of a spherical mirror is 20 cm. What is its focal length?

Define the principal focus of a concave mirror.