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Lesson 1 Reflection.

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Presentation on theme: "Lesson 1 Reflection."— Presentation transcript:

1 Lesson 1 Reflection

2 الانعكاس Optics الفهرس الانعكاس الصور في المرايا الكروية الانكسار
الصور في العدسات تطبيقات الانكسار

3 الأهداف Goals القانون الأول للانعكاس القانون الثاني للانعكاس
نوعا الانعكاس المرآة المستوية

4 المصطلحات key words سطح عاكس reflecting surface الشعاع الساقط
عمود الانعكاس الشعاع المنعكس زاوية السقوط زاوية الانعكاس القانون الأول للانعكاس القانون الثاني للانعكاس انعكاس منتظم انعكاس غير منتظم

5 نشاط -Activity-1

6 نشاط- Activity-2 ما المصطلح العلمي ؟
………………………………………… ارتداد الأشعة الضوئية عن السطح العاكس ………………………………………… شعاع ضوئي يسقط من المصباح على السطح العاكس ………………………………………… شعاع ضوئي يرتد عن السطح العاكس ………………………………………… الخط المعامد للسطح العاكس عند نقطة سقوط الأشعة على السطح العاكس : ………………………………………… الزاوية المحصورة بين الشعاع الساقط و عمود الانعكاس θi : ………………………………………… الزاوية المحصورة بين الشعاع المنعكس و عمود الانعكاس θr ……………………………………………………………………………” زاوية السقوط = زاوية الانعكاس“ ……………………………………………………..………………………الشعاع الساقط و الشعاع المنعكس و عمود الانعكاس تقـــع جميعاً في مستوى واحد عمودي على السطح العاكس

7 Law of reflection qi = angle of incidence qi qR
qR = angle of reflection 1st Law of reflection Planar reflecting surface (mirror)

8 نشاط-3-Activity θi = θR=
عين على الرسم كلاً من زاوية السقوط و الانعكاس ثم جد مقدار كلٍ منهما:- θi = θR= 40O مـــرآة

9 هل يتحقق قانونا الانعكاس في كلتا الحالتين؟ ..........
نوعا الانعكاس انعكاس انعكاس السطح السطح هل يتحقق قانونا الانعكاس في كلتا الحالتين؟

10 صفات الصورة في المرآة المستوية

11 Objects and images Object Image
Reflected rays appear to come from a point Rays from point on object reflect from mirror

12

13 17.1 Reflection Images appear in mirrors because of how light is reflected by mirrors. The incident ray follows the light falling onto the mirror. The reflected ray follows the light bouncing off the mirror.

14 Objects and images Object Image
Reflected rays appear to come from a point Rays from point on object reflect from mirror

15 صفات الصورة في المرآة المستوية
الصورة:- )حقيقية / وهمية ( خلف المرآة بُعد الصورة (أكبر / يساوي / أصغر ) بُعد الجسم حجم الصورة (أكبر/يساوي / أصغر ) حجم الجسم الصورة ( مقلوبة / معتدلة ) الصورة مقلوبة جانبياً

16 حجم الصورة يساوي حجم الجسم

17 الصورة مقلوبة جانبياً

18 التقويم يقف سعيد على بعـد 2m من مرآة.
ما بعد صورة سعيدعن المرآة؟ ………… ما بعد صورته عنه ؟ ………… يقترب طفل من المرآة بسرعة 0.4m/s . ما سرعة اقتراب صورة الطفل من المرآة؟ …………… ما سرعة اقتراب الطفل من صورته؟ ……………

19 Hall Mirror Useful to think in terms of images “real” you “image” you
Optics: Reflection, Refraction 05/25/2006 Hall Mirror Useful to think in terms of images “real” you “image” you mirror only needs to be half as high as you are tall. Your image will be twice as far from you as the mirror. Lecture 16 19

20 نشاط -Activity-4 ما الطول المطلوب للمرآة المستوية اللازم لكي صورتك كاملةً؟

21

22 parallel but opposite in direction
Example 1 A device consists of 2 mirrors at right angles to each other. Complete the path of the ray. M1 45 M2 The ray is turned back . 45 45 parallel but opposite in direction

23 How a plane mirror forms an image
Properties of the image formed by a plane mirror 1 behind the mirror; virtual 2 of same size as the object 3 laterally inverted 4 Image and object are Also see Simulation program 1.3 in Physics at Work Multimedia CD-ROM 1. object image equally distant mirror

24 Locating the position of the image
3 How a plane mirror forms an image Locating the position of the image by geometric construction O I virtual rays shown by dotted lines

25 3 How a plane mirror forms an image
Reflected rays appear to come from I behind the mirror. mirror I is a virtual image. cannot be picked up on a screen

26 Q3 True or false: Reflection of…
True of false: Reflection of light by a rough surface does not obey the laws of reflection. (T/F)

27

28 Q2 The angle between an… The angle between an incident ray and the mirror is 20. The angles of incidence and reflection are ____ and ____. 70 70 The mirror turns the ray by ____ . 140 20 70 70

29 Q1 The angle between the…
The angle between the incident ray and the _______ is called the angle of incidence. normal The laws of reflection state that it is equal to the angle of ___________. reflection

30 2 Regular and diffuse reflection
on a rough, not perfectly smooth surface e.g. cover of a book parallel incident rays reflected rays in different directions

31 2 Regular and diffuse reflection
Regular reflection on a flat, smooth surface e.g. mirror parallel incident rays parallel reflected rays

32 all lie in the same plane.
1st Law of reflection The incident ray, the reflected ray and the normal all lie in the same plane. normal incident ray reflected ray mirror normal incident ray reflected ray mirror

33 Angle of incidence = Angle of reflection
2nd Law of reflection Angle of incidence = Angle of reflection normal incident ray reflected ray mirror angle of incidence angle of reflection

34 Angle of incidence = Angle of reflection
The Law of Reflection Angle of incidence = Angle of reflection In other words, light gets reflected from a surface at ____ _____ angle it hits it. The same !!!

35 Using filters Filters can be used to “block” out different colours of light: Red Filter Magenta Filter

36 Clear vs. Diffuse Reflection
Smooth, shiny surfaces have a clear reflection: Rough, dull surfaces have a diffuse reflection. Diffuse reflection is when light is scattered in different directions

37 Angle of incidence = Angle of reflection
The Law of Reflection Angle of incidence = Angle of reflection In other words, light gets reflected from a surface at ____ _____ angle it hits it. The same !!!

38 Part 2 - Reflection Reflection from a mirror: Mirror Normal
Incident ray Reflected ray Angle of incidence Angle of reflection Mirror

39 Reflection We describe the path of light as straight-line rays
Optics: Reflection, Refraction 05/25/2006 Reflection We describe the path of light as straight-line rays Reflection off a flat surface follows a simple rule: angle in (incidence) equals angle out (reflection) angles measured from surface “normal” (perpendicular) Lecture 16 39

40 surface normal same angle exit ray reflected ray incident ray


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