Physics

Light - Reflection and Refraction

Question:

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

Answer:

Light-Reflection-and-Refraction-9

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Light - Reflection and Refraction

Q 1.

Distinguish between a real and a virtual image of an object. What type of image is formed (i) by a plane mirror, (ii) on a cinema screen? [Foreign]

Q 2.

State the type of mirror preferred as (i) rear view mirror in vehicles, (i0 shaving mirror. Justify your answer giving two reasons in each case.[Delhi] ?

Q 3.

Define one dioptre of power of a lens?

Q 4.

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

Q 5.

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.

Q 6.

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

Q 7.

A ray of light travelling in air enters obliquely into water. Does the light ray bend towards or away from the normal ? Why? Draw a ray diagram to show the refraction of light in this situation. [Delhi]

Q 8.

Define the focus of a concave mirror. If the radius of curvature of a convex mirror is 30 cm, what would be its focal length? [Foreign]

Q 9.

To construct a ray diagram, we use two light rays which are so chosen that it is easy to know their directions after reflection from the mirror. List these two rays and state the path of these rays after reflection. Use these rays to locate the image of an object placed between centre of curvature and focus of a concave mirror. [All India]

Q 10.

Which kind of mirrors are used in the headlights of a motor-car and why? [Foreign]

Q 11.

Redraw the diagram given below in your answer book and show the direction of the light ray after reflection from the mirror. [Delhi (C)]
light-reflection-and-refraction-chapter-wise-important-questions-class-10-science-25

Q 12.

Draw the ray diagram in each case to show the position and nature of the image formed when the object is placed:
(i) at the centre of curvature of a concave mirror
(ii) between the pole P and focus F of a concave mirror
(iii) in front of a convex mirror
(iv) at 2F of a convex lens
(v) in front of a concave lens

Q 13.

“The refractive index of diamond is 2.42”. What is the meaning of this statement in relation to speed of light? [Delhi]

Q 14.

What is the nature of the image formed by a concave mirror if the magnification produced by the mirror is +3? [Delhi]

Q 15.

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?

Q 16.

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

Q 17.

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.

Q 18.

Between which two points of a concave mirror should an object be placed to obtain a magnification of -3? [Delhi]

Q 19.

For which position of the object does a convex lens form a virtual and erect image? Explain with the help of a ray diagram. [All India]

Q 20.

The outer surface of a hollow sphere of aluminium of radius 50 cm is to be used as a mirror. What will be the focal length of this mirror? Which type of spherical mirror will it provide? [Delhi]

Q 21.

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

Q 22.

Name the type of mirror used in the following situations.
(a) Headlights ofa car
(b) Side/rear-view mirror of a vehicle
(c) Solar furnace
Support your answer with reason.

Q 23.

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

Q 24.

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

Q 25.

List four properties of the image formed by a plane mirror. [Delhi]

Q 26.

At what distance should an object be placed from a convex lens of focal length 18 cm to obtain an image at 24 cm from it on the other side. What will be the magnification produced in this case? [Delhi]

Q 27.

To instruct a ray diagram, we use two light rays which are so chosen that it is easy to know their directions after refraction from the lens. List these two rays and state the path of these rays after refraction. Use these two rays to locate the image of an object placed between ‘F and ‘2F of a convex lens. [Foreign]

Q 28.

List four properties of the image formed by a concave mirror, when object is placed between focus and pole of the mirror. [Delhi]

Q 29.

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

Q 30.

A convex lens has a focal length of 10 cm. At what distance from the lens should the object be placed so that it forms a real and inverted image 20 cm away from the lens? What would be the size of the image formed if the object is 2 cm high? With the help of a ray diagram show the formation of the image by the lens in this case. [All India (C)]

Q 31.

Redraw the diagram given below in your answer book and show the direction of the light ray after refraction from the lens. [Delhi, All India(C)]
light-reflection-and-refraction-chapter-wise-important-questions-class-10-science-29

Q 32.

How should a ray of light be incident on a rectangular glass slab so that it comes out from the opposite side of the slab without being displaced?  [Foreign]

Q 33.

A concave lens has focal length of 20 cm. At what distance from the lens a 5 cm tall object be placed so that it forms an image at 15 cm from the lens? Also calculate the size of the image formed. [Delhi]

Q 34.

If a light ray IM is incident on the surface AB as shown, identify the correct emergent ray. [Delhi (C)]

light-reflection-and-refraction-chapter-wise-important-questions-class-10-science-8

Q 35.

Redraw the diagram given below in your answer book and show the direction of the light ray after refraction from the lens. [All India (C)]
light-reflection-and-refraction-chapter-wise-important-questions-class-10-science-31

Q 36.

State the two laws of reflection of light. [Delhi]

Q 37.

An object 5.0 cm in length Is placedat a distanc, of 20 cm in front of a convex mirror of radius of curvature 30 cm. Find the position of the image nature and size.

Q 38.

Redraw the diagram given below in your answer book and show the direction of the light ray after reflection from the mirror. [Delhi (C)]
light-reflection-and-refraction-chapter-wise-important-questions-class-10-science-27

Q 39.

Why does a ray of light bend when it travels from one medium into another? [Delhi]

Q 40.

Name the type of mirror used in the following situations:
(i) Headlights of a car (ii) Rear-view mirror of vehicles (iii) Solar furnace Support your answer with reason. [All India][Foreign]

Q 41.

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

Q 42.

An object 50 cm tall is placed on the principal axis of a convex lens. Its 20 cm tall image is formed on the screen placed at a distance of 10 cm from the lens. Calculate the focal length of the lens. [All India]

Q 43.

An object 2 cm high is placed at a distance of 64 cm from a white screen. On placing a convex lens at a distance of 32 cm from the object it is found that a distinct image of the object is formed on the screen. What is the focal length of the convex lens and size of the image formed on the screen? Draw a ray diagram to show the formation of the image in this position of the object with respect to the lens. [Delhi(C)]

Q 44.

A girl was playing with a thin beam of light from her laser torch by directing it from different directions on a convex lens held vertically. She was surprised to see that in a particular direction the beam of light continues to move along the same direction after passing through the lens. State the reason for this observation. [Foreign]

Q 45.

Draw a ray diagram and also state the position, the relative size and the nature of image formed by a concave mirror when the object is placed at the centre of curvature of the mirror. [Delhi]

Q 46.

Define the principal focus of a concave mirror?

Q 47.

Redraw the given diagram and show the path of the refracted ray: [All India(C)]
light-reflection-and-refraction-chapter-wise-important-questions-class-10-science-13

Q 48.

Between which two points related to a concave mirror should an object be placed to obtain on a screen an image twice the size of the object? [All India]

Q 49.

A ray of light enters a rectangular glass slab of refractive index 1.5. It is found that the ray emerges from the opposite face of the slab without being displaced. If its speed in air is 3 x 108 ms-1 then what is its speed in glass? [Foreign]

Q 50.

In an experiment with a rectangular glass slab, a student observed that a ray of light incident at an angle of 55 ° with the normal on one face of the slab, after refraction strikes the opposite face of the slab before emerging out into air making an angle of 40 ° with the normal. Draw a labelled diagram to show the path of this ray. What value would you assign to the angle of refraction and angle of emergence? [All India]