PHY BK ANS 3A
3A Wave Motion I
1
Chapter 1
Reflection of Light
Reflection of Light
Practice 1.1 (p. 5)
1
C
2
C
3
Luminous objects: candle flame, lighted
(c)
lamps and the sun
Non-luminous objects: books, blackboards and the moon
(Or other reasonable answers)
4
(a) Divergent
(b) Divergent
(c)
5
5
Parallel
Angle of incidence = 90 25 = 65
Angle between the incident ray and the
(a)
reflected ray
= 65 + 65 = 130
6
(a) Angle of incidence = 90 30 = 60
(b)
(b)
(c)
Angle of reflection for the final reflected ray =z
= 90 y
Practice 1.2 (p. 10)
= 90 x
1
C
2
A
= 90 60
3
C
= 30
4
(a) Angle of incidence = 90 40 = 50
7
The surface of glossy paper is flat and light is reflected regularly. The large amount of light
(b) Angle of reflection
reflected by the glossy paper makes it difficult
= angle of incidence = 50
to read the prints.
New Senior Secondary Physics at Work
1
Oxford University Press 2009
3A Wave Motion I
8
Chapter 1
(a) When the surface of the water is ruffled,
8
Reflection of Light
(a)
diffuse reflection occurs to produce a distorted image.
(b) John’s explanation is wrong. The reflection of light still obeys the laws of reflection. The parallel rays are reflected towards different directions because the normals at different positions point towards different directions.
Practice 1.3 (p. 21)
1
A
2
D
3
A
4
C
(b) The image is of the same size as the object. 9
5
6
(a) Height of her image = 1.4 m
(b) Any two of the following: virtual; as far behind the mirror as the girl is in front; of the same size as the girl; erect; laterally inverted.
7
(a)&(b)
10
If the photograph is taken at an angle to the mirror surface, less light will be reflected by the mirror back to the camera and a better photograph will be taken.
11
(a) Distance setting = 3 m + 3 m
=6m
(b) No. This is because the camera focuses on the mirror instead of the image. The mirror is in front of the image to be photographed. New
1
Chapter 1
Reflection of Light
Reflection of Light
Practice 1.1 (p. 5)
1
C
2
C
3
Luminous objects: candle flame, lighted
(c)
lamps and the sun
Non-luminous objects: books, blackboards and the moon
(Or other reasonable answers)
4
(a) Divergent
(b) Divergent
(c)
5
5
Parallel
Angle of incidence = 90 25 = 65
Angle between the incident ray and the
(a)
reflected ray
= 65 + 65 = 130
6
(a) Angle of incidence = 90 30 = 60
(b)
(b)
(c)
Angle of reflection for the final reflected ray =z
= 90 y
Practice 1.2 (p. 10)
= 90 x
1
C
2
A
= 90 60
3
C
= 30
4
(a) Angle of incidence = 90 40 = 50
7
The surface of glossy paper is flat and light is reflected regularly. The large amount of light
(b) Angle of reflection
reflected by the glossy paper makes it difficult
= angle of incidence = 50
to read the prints.
New Senior Secondary Physics at Work
1
Oxford University Press 2009
3A Wave Motion I
8
Chapter 1
(a) When the surface of the water is ruffled,
8
Reflection of Light
(a)
diffuse reflection occurs to produce a distorted image.
(b) John’s explanation is wrong. The reflection of light still obeys the laws of reflection. The parallel rays are reflected towards different directions because the normals at different positions point towards different directions.
Practice 1.3 (p. 21)
1
A
2
D
3
A
4
C
(b) The image is of the same size as the object. 9
5
6
(a) Height of her image = 1.4 m
(b) Any two of the following: virtual; as far behind the mirror as the girl is in front; of the same size as the girl; erect; laterally inverted.
7
(a)&(b)
10
If the photograph is taken at an angle to the mirror surface, less light will be reflected by the mirror back to the camera and a better photograph will be taken.
11
(a) Distance setting = 3 m + 3 m
=6m
(b) No. This is because the camera focuses on the mirror instead of the image. The mirror is in front of the image to be photographed. New