# Reflection of Light

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Exercise of Reflection of LightMultiple Choice QuestionsLevel 1

1.

The figure above shows a large advertising board at night. Which of the following figures best shows how we can see the boards?

A.

B.

C.

D.

2.

Statement 1:Non-luminous objects cannot emit their own light.

Statement 2:We cannot see non-luminous objects.

A.Both statements 1 and 2 are correct and statement 2 is a correct explanation for statement 1.

B.Both statements 1 and 2 are correct but statement 2 is not a correct explanation for statement 1.

C.Statement 1 is correct and statement 2 is incorrect.

D.Statement 1 is incorrect and statement 2 is correct.

3.

The figure above shows a sunlight reflector installed on the roof of a building. At the instant shown, sunlight falls at an angle of 30 to the horizontal and is then reflected vertically into the building. What is the angle between the reflector and the horizontal?

A.30

B.45

C.60

D.75

4.

Which of the following statements about diffuse reflection are correct?

(1)Diffuse reflection does not obey the laws of reflection.

(2)A clear image would not be formed on a rough surface where diffuse reflection takes place.

(3)We can see non-luminous objects due to diffuse reflection.

A.(1) and (2) only

B.(1) and (3) only

C.(2) and (3) only

D.(1), (2) and (3)

5.

A point object O is placed in front of a plane mirror as shown. Which ray is a reflected ray coming from the object?

A.PB.QC.RD.S6.

Peter is standing 4 m in front of a plane mirror as shown. A lamp is located midway between Peter and the mirror. If Peter wants to take a clear photograph of the image of the lamp, at what distance should he focus?

A.2 m

B.4 m

C.6 m

D.8 m

7.

A baby is crawling towards a plane mirror at a velocity of 0.1 m s1. What is the velocity of his image?

A.0.2 m s1B.0.1 m s1C.0.1 m s1D.0.2 m s18.

A plane mirror moves towards a boy at a velocity of 2 cm s1. What is the velocity of his image?

A.4 cm s1B.2 cm s1C.2 cm s1D.4 cm s19.

The image formed by a plane mirror is said to be virtual because

A.it is laterally inverted.

B.it cannot be caught by a screen.

C.it is the same size as the object.

D.it cannot be seen.

10.

A boy of height 1.5 m stands in front of a plane mirror. In order for the boy to see his entire body, what is the minimum length of the plane mirror?

A.0.5 m

B.0.75 m

C.1.5 m

D.Cannot be determined unless the distance between the boy and the mirror is given

11.

An object is placed near one end of a periscope as shown. Which of the following figures best represents the image observed?

A. B. C. D. 12.

An object is placed near one end of a periscope as shown. Which of the following figures best represents the image observed?

A. B. C. D. 13.

A boy standing 2 m in front of a vertical plane mirror looks at the image of a picture 50 cm behind him as shown. What is the distance between the boy and the image of the picture?

A.2 m

B.2.5 m

C.4 m

D.4.5 m

14.

Which of the following diagrams correctly shows the formation of image by the plane mirror?

A. B. C. D. 15.

A ray of light falls on a horizontal plane mirror as shown.

In order to reflect the light ray vertically upwards, the plane mirror should be rotated by

Level 2

1.

In a room ABCD, a tall plane mirror of width 1 m is placed at the middle of the wall BD. The top view of the room is shown below.

A student facing the mirror wants to see the objects placed at corners A and C at the same time. At most how far can he stand away from the mirror?

A.2.25 m

B.3 m

C.5 m

D.6 m

2.

A girl is standing in front of a plane mirror which is hanging on the wall as shown in the figure. She is just able to see her feet through the mirror. In which of the following situations can she still see her feet through the mirror?

(1)The girl stands at the same position but raises the mirror.

(2)The girl walks towards the mirror.

(3)The girl walks away from the mirror.

A.(1) only

B.(3) only

C. (1) and (2) only

D.(2) and (3) only

3.

Two light ray emitted by a light source are reflected by two plane mirrors M1 and M2 as shown above. What is the angle between the two rays reflected by M2?

A.10(B.20(C.30(D.40(Structured Questions

Level 1

1.

A student proposes a liquid level indicator as shown above. When a beam of laser is directed towards the liquid surface, part of it is reflected towards the sensor.

(a)Find the angle of incidence at the instant shown.

(1 mark)(b)Briefly describe how the indicator works.

(2 marks)2.

(a)State the laws of reflection.

(2 marks)(b)A light ray strikes a plane mirror at an angle of incidence of 52.

(i)What is the angle between the incident ray and the reflected ray?

(1 mark)(ii)Sketch a ray diagram to illustrate your answer in (i).

(2 marks)

3.

(a)In the figure, sketch the image of the object formed by the plane mirror.

(1 mark) (b)State three properties of the image.

(3 marks)4.

A boy 1.3 m tall stands 3 m in front of a plane mirror. His eyes are 1.2 m above the ground.

(a)Draw a ray diagram to show how the boy sees himself in the mirror.

(2 marks)(b)Find the minimum length of the mirror for the boy to see his entire body.

(2 marks)5.

A boy stands 1 m in front of a plane mirror and just observes the image of a wall which is behind him. The mirror has a length of 0.8 m and it is 1 m above the ground. The distance between the mirror and the wall is 3 m.

(a)Find the height of the wall.

(2 marks)(b)The boy now stands 2 m in front of the mirror. Would he see the entire image of the wall? Explain your answer briefly.

(2 marks)6.

An observer looks at an object through a periscope as shown. The distance between the mirrors is 0.75 m. The object is 0.5 m away from the upper mirror while the observers eye is 0.25 m away from the lower mirror.

(a)State the nature of the image seen by the observer.

(3 marks)(b)What is the distance between the image formed by the lower mirror and the eye of the observer?

(2 marks)7.

A ray of light strikes a mirror as shown.

(a)(i)What is the line PQ?

(1 mark)(ii)Find the angle of incidence and the angle of reflection.

(2 marks)(b)Complete the following graph to show how the angle of reflection varies with the angle of incidence.

(2 marks)

8.

The figure below shows two plane mirrors M1 and M2 that are perpendicular to each other. A ray of light strikes M1 with an angle of incidence of 60(.

(a)Complete the path of the light ray.

(1 mark)(b)Find the angle of reflection of the light ray reflected by M2.

(2 marks)9.

(a)An object is placed in front of a plane mirror as shown in the figure above. Copy the figure into a piece of graph paper, draw the reflected rays and mark the position of the image.

(2 marks)(b)State three properties of the image formed.

(3 marks)

10.

A man, represented by the arrow HF stands 0.5 m in front of a large plane mirror as shown. The man is 1.8 m tall and his eyes are 1.7 m above the ground. A tree, represented by arrow TR has a height of 2.5 m. It is 2.5 m behind the man.

(a)Find the distance between the man and the image of the tree.

(2 marks)

(b)Draw, on the figure above, to show how the man sees the image of the tree.

(2 marks)

(c)Find the minimum length of the mirror for the man to see the entire tree.

(1 mark)

(d)If the man stands 2 m in front of the mirror, what would be the answer in (c)?

(2 marks)

Level 2

1.

Two boys, Jerry and Tom, are playing hide-and-seek. At the instant shown, Tom is hiding behind an opaque board such that Jerry cannot see him in the mirror.

(a)In which direction, A or B, should Jerry move if he wants to see Tom in the mirror?

(1 mark)(b)What is the minimum distance that Jerry has to travel?

(2 marks)2.

In each of the following cases, how would you arrange a pair of plane mirrors inside the box to produce the result as shown?

(a)

(1 mark)

(b)

(1 mark)

3.

An object AB is placed in front of a plane mirror as shown.

(a)(i)Draw the reflected rays and hence locate the position of the image.

(2 marks)

(ii)State the nature of the image.

(3 marks)(iii)Find the magnification of the image.

(2 marks)(b)The figure below shows an object placed in front of a periscope. Complete the paths of the two light rays and hence locate the images formed by the two mirrors.

(2 marks)

4.

A beam of light is directed to a vertical plane mirror as shown in figure (a).

(a)Find the angle of incidence and angle of reflection. Draw and label the normal, the reflected ray, the angle of incidence and the angle of reflection on the figure.

(4 marks)(b)Without altering the direction of the beam, the mirror is rotated through an angle ( in a clockwise direction (where ( is smaller than 60() as shown in figure (b). Find the new angle of reflection in terms of (.

(2 marks)

(c)Using the original position of the mirror as a reference li