PHYSICS - CAMBRIDGE -1ST SECONDARY

1. 7.4
REFRACTION

2. REFRACTION
LOOK AT THIS PHOTO
-Pencil in a glass of water
-The pencil appears to be broken but isn’t
The light coming from the bottom half of
the pencil is changing direction as it
travels because of the boundary between
the water and the air
2

3. Explain why !
The rays of light coming from
the pencil are refracted at the
boundaries between materials
3

4. “REFRAC TION”
is the change in the direction of light
when it moves from one transparent
material to another
4

5. Expert tips
• Refraction happens at boundaries so always draw diagrams
showing the light rays changing direction at the boundary.
• Remember to always measure angles from the normal !
5

6. Key terms
6

7. 1.ANGLE OF INCIDINCE
The angle between the incident light ray and the normal
2.ANGLE OF refraction
The angle between the refracted
light ray and the normal
3.The normal
A line at right angles to the boundary

8. EXPLAINING REFRACTION
8
The light changes speed
as it moves between
materials
Refraction
happens
because

9. IMPORTANT concepts
When a ray of light moves fro air to
water(glass) between two materials it slows
down , and refracts towards the normal
9
When a ray of light moves fro water(glass) to
air between two materials it speeds up , and
refracts away from the normal
😉

10. SIR.MUHAMMAD ABDUL MAGEID