Optics full view

3. What is Refraction?
Refraction
The bending of light rays as they pass between
two different medium
Why does refraction occur?
Refraction occurs due to changes in the speed of light
in different mediums
Air
medium
Water
medium

4. • Rarer Medium
Air Medium
• Denser Medium
Water
Medium
Air
Medium
Water
Medium
Normal

5. Refraction Example

6. Refraction Example

7. Refracted ray :
Ray of light that is
bent when entering a
second medium
Angel of Refraction
Angle between the
normal and refracted ray
Air
Medium
Water
Medium
Incident
Ray
Refracted
Ray
Normal
Angle of
Refraction
Angle of
Incidence

8. Ration between speed of light in vacuum to
its speed in specific medium
Index of refraction
of material =
μ

9. Snell’s law
Relationship between the angle of incident and refraction
of the indices of refraction of 2 mediums (μ)
Normal
μ1 (air)
μ2
(water)
Sin i

10. Air
Medium
Incident
Ray
Normal
Angle of
Refraction
Honey
Medium
Normal

11. Composite Light

12. Refraction in Nature

13. Dispersion of light
Dispersion
The refraction of white light into
separate wavelengths(color)
The amount of refraction is
different for each color

14. Angle of refraction
Angle of refraction Smallest for Red
Highest for Violet

15. Scattering of light
Incident Light ray
Scattered light

16. Energy of the incident beam of light=
Energy of the scattered beam of light
Ground state
Excited state
Incident
light
Scattered
light

17. Energy of the incident
beam of light ≠ Energy of the scattered
beam of light
Ground state
Excited state Excited state
Ground state
Low
Frequency
High Frequency
Incident
light
Incident
light
Scattered
light
Scattered
light

18. Why does sun appear reddish at sunrise and sun set
Relay's scattering
“The amount of scattering of light is
inversely proportional to the fourth power
of its wavelength”.

19. Tyndall Effect

20. Raman Scattering
(Change Wavelength or frequency)
The scattered light contains some additional frequencies (or
wavelengths) other than that of incident frequency (or wavelength).
This is known as Raman scattering or Raman Effect.

21. Ground state
Excited state Excited state
Ground state
Incident
light
Incident
light
Scattered
light
Scattered
light
Ground state
Excited state
Incident
light
Scattered
light
Rayleigh
Line
Stokes
Line
AntiStokes
Line
Equal
frequency
Low
frequency
High
frequency

23. Convex Lens
Plano-Convex
Bi-Convex lens
Convex lens
Positive
meniscus

24. Plano-Convex
Bi-Convex lens

25. Concave Lens
Concave
Lens
Bi-Concave
Lens
Plano-Concave
Lens
Negative
Meniscus

26. Convex lens Concave lens

28. Telescope
Human Eyes Magnifying lens
Microscope
Eyeglass
Camera
Projector

29. Binocular
Flash light
Door viewers
Eyeglass

30. Principle
axis
Principle
Focus(F1)
Principle
Focus(F2)
Optical
center
Center of
curvature (2 F1)
Center of
curvature(2 F2)

31. Image formed due to refraction convex and concave
Rule 1: Optical centre(Obliquely)
F2
F1
2 F1 2 F2
F2
F1
2 F1 2 F2

33. Rule 2: Light ray passing through parallel to principle
axis
F2
F1
2 F1 2 F2
F2
F1
2 F1 2 F2

34. Rule 3 : Light ray passing through the principle axis
F2
F1
2 F1 2 F2
F1 F2
2 F2
2 F1

35. Refraction through a convex lens
when placing object infinity
F2
F1
2 F1 2 F2
*Image formed at the principle focus
*Highly diminished
*Real and inverted

36. F2
F1
2 F1 2 F2
When the object is beyond Centre of curvature
Image formed between
principle focus and centre of curvature
It is diminished
Real and inverted

37. When the object is at Centre of curvature
F2
F1
2 F1
2 F2
Image is the same size as the object
Real and inverted

38. F2
F1
2 F1
2 F2
When the object is between
Centre of curvature and Principle focus
The image is formed beyond Centre of curvature
It is enlarged
Real and inverted

39. F2
F1
2 F1
2 F2
When the object is at Principle focus
The image is formed at infinity
It is highly enlarged
Real and inverted

40. F2
F1
2 F1
2 F2
When the object between
principle focus and lens
Image is formed on the same side of the lens
It is enlarged
Virtual and erect

41. Animation

42. Refraction through a concave lens
when placing object infinity
F2
F1
2 F1 2 F2
•virtual image is formed at the focus.
•The size of the image is much smaller than
that of the object

43. F1
2 F1
Object anywhere on the principal axis at
a finite distance
•A virtual image is formed
between optical center and
focus of the concave lens.
•The size of the image is smaller
than that of the object

44. Object Image
u v
Lens
1 1 1
__ -- ____ = ____
v u f
u =object distance
v = Image distance
f = Focal length

45. Sign convention for spherical lenses
Focal length of convex lens is +
Focal length of concave lens is -
O Distance towards the right (+ve)
Height
Upwards
(+ve)
Direction of
incident light
Distance towards
the left (-ve)
Height
downwards
-ve
Object
Image

46. Magnification produced by spherical lenses
Magnification for spherical lens is the
ratio of the height of the image to the
height of the object
Height of the image
------------------------------
Height of the object
Magnification=

47. Magnification m =
Object distance v
-------------------------- = ----
Image distance u
Magnification produced by
spherical lenses

48. Power of lens
The power of a lens is the reciprocal of its focal length
P =
1
-----
f
The SI unit of power is dioptre (D)
The power of a convex lens is positive (+ve)
The power of a concave lens is negative (-ve)

49. Human Eye
Human eye is very sensitive part
 It has 2 million working part
Eye are the Fast working part in the human body
 Diameter of eye is 2.3 cm
Spherical shape
Internal part protected by ciliary muscles
Eyes are captured 50 different object in one second

58. The ability of the eye to adjust itself and
focus objects lying at different distance
is called the Power of accommodation of the eye

59. Long distance
When the ciliary muscles are relaxed,
then eye lens becomes thin
Thus its focal length increase and
we see the distant object clearly

60. When the ciliary muscles are contract , then the
curvature of the eye lens is increases and the
lens becomes thick.
Thus, its focal length decreases.We see the
nearby object clearly

61. Persistence of vision
(less than .0.01 sec

62. Near point of the eye
Near point or least distance of distinct
vision is the point nearest to the eyes at
which an object is visible distinctly

63. Far point of the eye
Far point of the eye is the maximum
distance up to which the normal eye
can see things clearly.
It is infinity for a normal eye

64. Defects of Vision and Their Correction
Myopia or Near-sightedness
Hypermetropia or Farsightedness
Presbyopia
Astigmatism

65. Normal Eye

67. Myopia or Near-Sightedness
The light from a distant object arriving at the
eye lens may get Converged at a point in
front of
the retina in the vitreous body

68. Correction for Myopia
To compensate this, we interpose a
concave lens between the eye and the object,
With the diverging effect desired to get
the image Focused on the retina

70. Hyperemetropia or Farsightedness
If the eye-lens focuses the
incoming light at a point behind the retina,
This defect is called far sightedness or
hypermetropia

71. Correction for Hypermetropic eye
Convex lens
(Convergent lens)
is needed to compensate
for the defect in vision

72. Presbyopia
Presbyopia is a common type of vision
disorder that occurs as old age.
It is often referred to as the aging eye condition.
Presbyopia results in the inability to focus up close,
a problem associated with refraction in the eye.

73. Presbyopia

74. Presbyopia

75. Astigmatism

76. Simple microscope
•It is used in pedology (a
study of soil particles)
•It is used by a dermatologist
to find out various skin
diseases.
•It is used in microbiology to
study samples of algae, fungi
etc
•It is used by the jewelers to
get a magnified view of the
fine parts of the jewellery.
Simple microscope has a convex lens
of short focal length…It is held near the
eye to get enlarged image of small object

79. The identification of diseases becomes
easy in pathology labs with the help
of a compound microscope.
Forensic laboratories use compound
microscopes for the detection of human
fingerprints.
The presence of metals can be detected
with the help of a compound microscope.
The study of bacteria and viruses becomes
easy with the help of a compound microscope.
Schools use compound microscopes for
academic purposes.
Uses of Compound microscope

80. Telescope

81. Types of Telescope
Telescope
Optical
property
Refracting
telescope
Reflecting
telescope
Things
observed
Astronomical
telescope
Terrestrial
telescope

82. Refracting telescope:
Binoculars are a combination of two
parallel telescopes fixed to one another. As
opposed to other telescopes, binoculars are
more comfortable to use since they allow
users to observe objects from both eyes
instead of a single eye.
Refracting Telescope
Used in long focus
camera
Used in astronomical telescope

83. Refracting Telescope

84. Reflecting Telescopes.
Reflectors were invented shortly after
refractors, and some people suggest that
their design was an improvement of its
predecessor.
Reflecting Telescope

86. Astronomical Telescope
Used to view Stars, Planets,
Galaxies, Satellites

87. Space View

88. Terrestrial Telescope
The image in an astronomical telescope is
inverted.
So, it is not suitable for viewing objects on
the surface of the Earth.
Therefore, a terrestrial telescope is used.
It provides an erect image.
The major difference between astronomical
and terrestrial telescope is erecting the final
image with respect to the object