Light Class 8 PPT

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CHAPTER - 16 
 
LIGHT 
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CHAPTER - 16 
 
LIGHT 
1) What makes things visible :- 
     Light helps us to see objects. We cannot see objects in 
the dark.  
     An object becomes visible when light emitted or 
reflected by it reaches our eyes. 
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CHAPTER - 16 
 
LIGHT 
1) What makes things visible :- 
     Light helps us to see objects. We cannot see objects in 
the dark.  
     An object becomes visible when light emitted or 
reflected by it reaches our eyes. 
2) Reflection of light :- 
    When light falls on a polished or shiny surface it 
changes its direction. This is called reflection of light. 
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CHAPTER - 16 
 
LIGHT 
1) What makes things visible :- 
     Light helps us to see objects. We cannot see objects in 
the dark.  
     An object becomes visible when light emitted or 
reflected by it reaches our eyes. 
2) Reflection of light :- 
    When light falls on a polished or shiny surface it 
changes its direction. This is called reflection of light. 
   The ray of light which strikes the surface is called incident ray. The 
ray which comes back after reflection is called reflected ray. The 
perpendicular line drawn at the point of incidence is called normal. The 
angle between the normal and incident ray is called angle of incidence 
(    i ) . The angle between the normal and reflected ray is called angle of 
reflection(    r ) . 
   The angle of incidence is always equal to the angle of reflection. 
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CHAPTER - 16 
 
LIGHT 
1) What makes things visible :- 
     Light helps us to see objects. We cannot see objects in 
the dark.  
     An object becomes visible when light emitted or 
reflected by it reaches our eyes. 
2) Reflection of light :- 
    When light falls on a polished or shiny surface it 
changes its direction. This is called reflection of light. 
   The ray of light which strikes the surface is called incident ray. The 
ray which comes back after reflection is called reflected ray. The 
perpendicular line drawn at the point of incidence is called normal. The 
angle between the normal and incident ray is called angle of incidence 
(    i ) . The angle between the normal and reflected ray is called angle of 
reflection(    r ) . 
   The angle of incidence is always equal to the angle of reflection. 
3) Laws of reflection of light :- 
    The laws of reflection of light are :- 
 i) The angle of incidence is equal to the angle of reflection. 
ii) The incident ray, the reflected ray and the normal at the 
point of incidence all lie in the same plane.  
i 
r 
Normal 
Incident rays Reflected rays