chapter 5

refraction Snell law Total internal
reflection
Glass,
lens • i>c
• Ligth travel denser
reflection
Law of reflection to less dense
NobtyfoArKsTalPe
mirror Plane
Plane mirror, mirror
convex mirror, Virtual, upright,
concave mirror same size, lateral
inverted, distance
object=distance
image

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NobtyfoArKsTalPe

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Reflection

Reflection •Law of reflection
•Angle incident=angle reflection

•Virtual , upright. Lateral inverted
•Distance image =distance object
•Size image = size of object
Plane Mirror NobtyfoArKsTalPe

•Virtual, upright and diminished
• Conner mirror, side mirror
Convex mirror •Wider field of view

Position of object Characteristics of image Application
U<f Virtual, upright magnify Dental mirror

Concave U=f Infinity Parabolic of torchlight
mirror
c>u>f Real, inverted, magnify

U=c Real, inverted, same size

u>c Real, inverted, diminished

U=œ Real, inverted, diminished Parabola disc

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Light change direction and speed when enter
different density of medium

Light Speed Direction
wave
High Away from normal
Low Low line (angle greater)
density
Toward normal line
High (angle smaller)
density NobtyfoArKsTalPe Snell;s law Higher density material,
greater refractive index

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Higher refractive index, smaller NobtyfoArKsTalPe Angle incident=angle of reflection
critical angle. Easy to reflect
• The light ray must be travel from an optically
a phenomenon which occurs denser medium to less dense medium.
when a propagating wave
strikes a medium boundary • The angle of incidence must be greater than
at an angle larger than a the critical angle.
particular critical angle.

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Optical fiber NobtyfoArKsTalPe Binocular

Mirage

Fish eyes’ view Periscope 7

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NobtyfoArKsTalPe

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Convex lens

NobtyfoArKsTalPeImage : Virtual, upright, magnifyImage : Real, Inverted, magnify

Image : Virtual, upright, dimimished

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Concave Lens

ff
NobtyfoArKsTalPe

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Concave mirror

Cf
NobtyfoArKsTalPe

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Convex mirror

Cf
NobtyfoArKsTalPe

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Same size

Real Virtual
inverted Upright
NobtyfoArKsTalPe
diminished 2f f f

magnify simulator
simulator

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NobtyfoArKsTalPe

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NobtyfoArKsTalPe Virtual
Inverted
compare to
obj,
magnified

M=moXme

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fo>>>>>>>fe M=fo/feNobtyfoArKsTalPe

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P= NobtyfoArKsTalPe1
v
1 = 1 +
fu

 m=v CHAPTER 5 LIGHT Alan Kho 19
u

OR
 m = hi
 ho





Linear Size of image
magnification,m
Convex lens Concave lens
Object distance Always + Always + ImI =1 Image and object
,u are the same size
Object is always Object is always
placed to the left of placed to the left of When m=1,
V=U=2f
the lens the lens

Image + if the image + if the image is realNobtyfoArKsTalPe
distance, v is real ( image is ( image is formed on
formed on the the right side of the
right side of the ImI >1 Enlarged image,
lens. ImI <1 V>U
lens. - if the image is
- if the image is virtual ( image is Diminished image,
virtual ( image formed on the left V<U
side of the lens.
is formed on
the left side of

the lens.

Focal Always + Always -
length, f Always + Always -
Power of
length, P CHAPTER 5 LIGHT Alan Kho 20