ĐỊNH LUẬT PHẢN XẠ ÁNH SÁNG THE LAW OF REFLECTION Memorize The law of reflection: •A reflection ray lies in a plane containing an incident and a normal of the mirror at an incident point[r]
Trang 1TIẾT 4 ĐỊNH LUẬT PHẢN XẠ ÁNH SÁNG
(THE LAW OF REFLECTION)
Trang 2BÀI 4 ĐỊNH LUẬT PHẢN XẠ ÁNH SÁNG
( THE LAW OF REFLECTION)
VACABULARY
Reflection : phản xạ
Image: ảnh
Incident ray: tia tới
Perpendicularly: vuông góc
Normal: đường pháp tuyến
Angle: góc
Trang 3BÀI 4 ĐỊNH LUẬT PHẢN XẠ ÁNH SÁNG
( THE LAW OF REFLECTION)
I PLANE MIRROR
The image of an object observed in mirror is
called the image of an object created by a
plane mirror
C1 Sheet metal smooth and flat, water surface,
glass,
C1 Indicate some objects which have flat, smooth surfaces and can be used to see image of our
as a plane mirror
II THE LAW OF REFLECTION
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( THE LAW OF REFLECTION)
I PLANE MIRROR
The image of an object observed in mirror is
called the image of an object created by a
plane mirror
II THE LAW OF REFLECTION
Phenomenon of light rays coming from the
mirro faces in a definite direction is called
light refrection phenomenon
1 What plane does the reflected ray lie in?
C2 Observe and tell what plane does the reflected ray lie in?
Conclusion: Reflected ray is in the same
plane with……… and……… incident ray nomal
Trang 5BÀI 4 ĐỊNH LUẬT PHẢN XẠ ÁNH SÁNG
( THE LAW OF REFLECTION)
Conclution: Reflected ray is in the same plane with
incident ray and normal
I PLANE MIRROR
II THE LAW OF REFLECTION
1 What plane does the reflected ray lie in?
2 How is the direction of a reflected ray
related to the direction of an incident ray?
Angle SIN= i is called angle of incident
Angle NIR= i’ is called angle of reflection
IN lie perpendicularly with the mirror surface
is called normal
Conclusion: An angle of reflection is always
……….angle of incidentequals
Angle of incidence i
Angle of reflection i’
600
450
300
600
450
300
I
S N
R
Trang 6BÀI 4 ĐỊNH LUẬT PHẢN XẠ ÁNH SÁNG
( THE LAW OF REFLECTION)
Conclusion: Reflected ray is in the same plane with
incident ray and normal
I PLANE MIRROR
II THE LAW OF REFLECTION
1 What plane does the reflected ray lie in?
2 How is the direction of a reflected ray
related to the direction of an incident ray?
Conclusion: An angle of reflection is always equals
angle of incident
3 The law of reflection
Angle of incidence i
Angle of reflection i’
600
450
300
600
450
300
Trang 7BÀI 4 ĐỊNH LUẬT PHẢN XẠ ÁNH SÁNG
( THE LAW OF REFLECTION)
I PLANE MIRROR
II THE LAW OF REFLECTION
4 Ketch a plane mirror and light ray
I Incident point Plane miror
C3.
Reflected ray is in the same plane with incident ray
and normal
1 What plane does the reflected ray lie in?
2 How is the direction of a reflected ray
related to the direction of an incident ray?
An angle of reflection is always equals angle of incident
3 The law of reflection
Trang 8BÀI 4 ĐỊNH LUẬT PHẢN XẠ ÁNH SÁNG
( THE LAW OF REFLECTION)
Reflected ray is in the same plane with incident ray
and normal
I PLANE MIRROR
II THE LAW OF REFLECTION
1 What plane does the reflected ray lie in?
2 How is the direction of a reflected ray
related to the direction of an incident ray?
An angle of reflection is always equals angle of incident
3 The law of reflection
N
R
S
I C4.
III APPLICATION
4 Ketch a plane mirror and light ray
Trang 9BÀI 4 ĐỊNH LUẬT PHẢN XẠ ÁNH SÁNG
( THE LAW OF REFLECTION)
Reflected ray is in the same plane with incident ray
and nomal
I PLANE MIRROR
II THE LAW OF REFLECTION
1 What plane does the reflected ray lie in?
2 How is the direction of a reflected ray
related to the direction of an incident ray?
An angle of reflection is always equals angle of incident
3 The law of reflection
S N
R
I
C4.
S
N
R I
a)
b)
III APPLICATION
4 Ketch a plane mirror and light ray
Trang 10BÀI 4 ĐỊNH LUẬT PHẢN XẠ ÁNH SÁNG
( THE LAW OF REFLECTION)
Memorize
The law of reflection:
•A reflection ray lies in a plane containing an incident
and a normal of the mirror at an incident point
•The angle of reflection equals the angle of incident