3 - 12 Light waves
● ***ALL light waves are transverse, can ALL be reflected, refracted and diffracted
Reflection
● Click here......
More on - refraction
● ***In vacuum/air, ALL light waves travel at same speed of 3 * 108 m/s
● HOWEVER light waves travel at different speeds in different media, e.g.: in glass,
speed of light is ≈2 * 108 m/s
○ ∴ When ray of light travels from air into glass, light slows down as
crossing border between two media; change in speed may cause ray to
change direction
1
, ●
● Refractive index
sini
○ ***n=
sin r
● Total internal reflection
○ ***Definition: complete reflection of ray of light within medium from
surrounding surfaces back into medium
2
● ***ALL light waves are transverse, can ALL be reflected, refracted and diffracted
Reflection
● Click here......
More on - refraction
● ***In vacuum/air, ALL light waves travel at same speed of 3 * 108 m/s
● HOWEVER light waves travel at different speeds in different media, e.g.: in glass,
speed of light is ≈2 * 108 m/s
○ ∴ When ray of light travels from air into glass, light slows down as
crossing border between two media; change in speed may cause ray to
change direction
1
, ●
● Refractive index
sini
○ ***n=
sin r
● Total internal reflection
○ ***Definition: complete reflection of ray of light within medium from
surrounding surfaces back into medium
2
