Transcript CHAPTER-17 Light and Image Formation

CHAPTER-17
Light and Image Formation
Chapter Outline
1 Reflection and Image Formation
2 Refraction of Light
3 Lenses and Image Formation
4 Focusing Light with Curved mirrors
5 Eyeglasses, Microscopes, and Telescopes
Everyday Phenomenon:
Rainbows and Laser Refractive Surgery
How Does an Image Formed in a
Mirror?
How Are Light Rays Related to
wavefronts?
Wavefronts are perpendicular
to the rays.
Reflection
The Law of Reflection
The angle of incidence = The angle of reflection.
i  r
How Are Images Formed by a
Plane Mirror?
How Are Images Formed by a
Plane Mirror?
Q7
Refraction of Light
Definition Of The Index Of
Refraction
The index of refraction n of a material is the ratio of the speed
c of light in a vacuum to the speed v of light in the material:
Law of Refraction
n1 Sin1  n2 Sin 2 .
Apparent Depth of Fish Is
Smaller Than Actual Depth Due
to Refraction
Total Internal Reflection
Why a Diamond Sparkles?
Why does a diamond exhibit such brilliance? And why does a
diamond lose much of its brilliance when placed under water?
Optical Instruments
Many optical instruments, such as binoculars, periscopes, and
telescopes, use glass prisms and total internal reflection to turn a
beam of light through 90° or 180°.
Prism and Spectrum of
Colors
Dispersion of Light
Rainbow
Primary Rainbow
Water droplet
disperses the
light into
colors.
Secondary Rainbow
Colors are reversed and less intense.
Focal Point (F) and Focal
Length (F)
Ray Diagram
Ray Diagram
Diverging or Negative lens:
Focal Point (F) and Focal
Length (f)
Ray Diagram for Diverging Lens
Lens Equation
Lens Equation and
Magnification, m
E6
Optical Instruments
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Human eye
Camera
Eyeglasses
Microscope
Telescope
Vision Defects
• Nearsightedness: can see only nearby objects
clearly.
• Farsightedness: can see only far objects clearly.
Nearsighted Eye, Myopia
Negative Lens Is Used to Correct
Nearsightedness
Positive Lens Is Used to Correct
Farsightedness
How Does a Microscope Work?
• Used to view small things nearby.
• Consists of two positive lenses, objective
and eyepiece.
• Final image is magnified and inverted.
• Ray diagram can be used to illustrate the
image formation.
Ray Diagram For Microscope
Microscope
A laboratory microscope
has 3 or 4 objective
lenses.
Astronomical Telescope
LASIK