PPT: Light | Science Class 8 PDF Download

 Page 1


Lesson context Key concepts Activity Investigation
LIGHT
Page 2


Lesson context Key concepts Activity Investigation
LIGHT
Key concepts Activity
What Makes Things Visible?
Light rays travel in straight
lines from a source.
When these light rays hit an
object, they can bounce off
its surface and into our eyes.
This bouncing off is called
reflection
This is how we see objects.
Page 3


Lesson context Key concepts Activity Investigation
LIGHT
Key concepts Activity
What Makes Things Visible?
Light rays travel in straight
lines from a source.
When these light rays hit an
object, they can bounce off
its surface and into our eyes.
This bouncing off is called
reflection
This is how we see objects.
Key concepts Activity Investigation
Non-luminous objects
are objects which
reflect light from other
sources. They do not
emit light of their own.
Luminous objects vs Non Luminous objects
Luminous objects
are objects which
emit light of their
own
Page 4


Lesson context Key concepts Activity Investigation
LIGHT
Key concepts Activity
What Makes Things Visible?
Light rays travel in straight
lines from a source.
When these light rays hit an
object, they can bounce off
its surface and into our eyes.
This bouncing off is called
reflection
This is how we see objects.
Key concepts Activity Investigation
Non-luminous objects
are objects which
reflect light from other
sources. They do not
emit light of their own.
Luminous objects vs Non Luminous objects
Luminous objects
are objects which
emit light of their
own
Activity
The ray of light which falls on the
mirror surface is called an incident
ray. 
1.
The point where this light touches the
mirror is the point of incidence.
2.
 The light that bounces back is the
reflected ray. 
3.
The ‘normal’ is a line drawn at right
angles to the mirror surface at the
point of incidence. 
4.
The angle between the incident ray
and normal is called the angle of
incidence. 
5.
The angle between the reflected ray
and normal is called the angle of
reflection.
6.
Reflection of Light
Page 5


Lesson context Key concepts Activity Investigation
LIGHT
Key concepts Activity
What Makes Things Visible?
Light rays travel in straight
lines from a source.
When these light rays hit an
object, they can bounce off
its surface and into our eyes.
This bouncing off is called
reflection
This is how we see objects.
Key concepts Activity Investigation
Non-luminous objects
are objects which
reflect light from other
sources. They do not
emit light of their own.
Luminous objects vs Non Luminous objects
Luminous objects
are objects which
emit light of their
own
Activity
The ray of light which falls on the
mirror surface is called an incident
ray. 
1.
The point where this light touches the
mirror is the point of incidence.
2.
 The light that bounces back is the
reflected ray. 
3.
The ‘normal’ is a line drawn at right
angles to the mirror surface at the
point of incidence. 
4.
The angle between the incident ray
and normal is called the angle of
incidence. 
5.
The angle between the reflected ray
and normal is called the angle of
reflection.
6.
Reflection of Light
Activity
The incident ray, the
reflected ray, and the
normal (at the point
of incidence), all lie
in the same plane.
1.
The angle of
reflection is always
equal to the angle of
incidence.
2.
Laws of Reflection