Abdul Rauf bin Ramli

200px-Refraction-with-soda-straw.jpg

Reflection and Refraction of Light
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The Law's
1.The Law of reflection states that when a ray of light reflects off a surface,the angle of incidence is equal to the angle of reflection and the incident,normal and reflected ray is on the same plane.

755px-MtHood_TrilliumLake.jpg

2.The Law of refraction states that the ratio of the sine of the angle of incidence and the sine of the angle of refraction of a wave are constant when it passes between two given media.

Extra Notes
-Photoelectric effect is a quantum electric phenomenon in which electrons are emitted from matter after the absorption of energy from electromagnetic radiation such as x-rays or visible light.
275px-Photoelectric_effect.svg.png

Done by,
Abdul Rauf

Adrian Ong Chong Ming

1. Light that is reflected has the same angle of incidence as the incident of reflection.
2. Light cannot penetrate through opaque objects

Aishah Nadirah binti Noor Azman Yusof

external image lavalampnightlight.jpg

Properties of Light
1. Light travels in a straight line
2. Light can be refracted
  • bending of light ray when it enters a medium of different density
- e.g. Medium to higher density : the speed increases
Lower to higher density : the speed decreases
3. Light can be reflected
4. Light acts as an electromagnetic wave
  • external image Young_Diffraction.png
- Thomas Young's Wave Theory
5. Light travels 300 000 000 000 000 m/s in vacuum
  • external image Speed_of_light_from_Earth_to_Moon.gif
- Diagram : speed of light from the Earth to the Moon

Extra Information
How A Prism Works
external image rainbow-prism.jpg

Done by,
Aishah Nadirah


Aisyah binti Zainal Abidin


Alia Syakiera binti Mohd. Zuhri


Alicia Lee Su Yin (Ally)

Refraction of Light

- Refraction
of light is the bending of a light ray when it enters a medium of different density.
- The Law of Refraction states that the ratio of the sine of the angle of incidence and the sine of the angle of refraction of a wave are constant when it passes between two given media.
- From a medium of higher density to a medium of lower density, the speed of light increases.
- From a medium of lower density to a medium of higher density, the speed of light decreases.
- From a medium of higher density to a medium of lower density, the ray of light is refracted away from the normal.
- From a medium of lower density to a medium of higher density, the ray of light is refracted towards the normal.

Examples :

a) When light travels from one medium to a different medium, the light ray will be refracted in a different direction.

refraction_ray.gif

b) When light travels from a medium of lower density to a medium of higher density, the ray of light is refracted towards the normal.

refractionlaw.jpg
c) When light travels from a medium of higher density to a medium of lower density, the ray of light is refracted away from the normal.

critical1.gif

Applications of Refraction of Light :

a) The bending of a straw when seen in a glass of water.

glass_of_water.jpg

b) The forming of a spectrum through a prism.

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Andrea Chan Su Lyn


Ashleigh Yeap Jing Wen


Aw Kah Long


Chew Qq Ee

Reflection of light


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Here are descriptions for the terms in this diagram :
- The ray of light which strikes the surface is called the incident ray.
- The ray of light which leaves the surface is called the reflected ray.
- A line perpendicular line to the surface is imagined at the point of reflection. This line is called a normal.
- The angle between the incident ray and the normal is called angle of incidence or the incident angle.
- The angle between the reflection ray and the normal is called angle of reflection or the reflected angle.

Check this web site : http://id.mind.net/~zona/mstm/physics/light/rayOptics/reflection/reflection1.html


Danial Iskandar Shah


Foong Chea Yean (Melanie)


Joanna Sangeetha Vijaykumar


Kathryn Gan Xin-Yi

-Reflection of light-

1. Light can be reflected. Reflection of light is the change in direction of a light ray when it hits a surface of an opaque object and bounces off the object.

2. When the reflected light rays enter our eyes, we can see the object.

3. Mirrors and sheets of glass are highly polished surfaces. These surfaces reflect light regularly.

4. Regular reflection happens when a parallel beam of light remains parallel after reflection from an even surface.

5. The surfaces of most objects are not even.

6. Paper, unpolished planks and cloth are examples of uneven surfaces. When a parallel beam of light falls on an uneven surface, the rays are reflected in different directions from the surface. This is called irregular reflection.

http://www.rebeccapaton.net/rainbows/rflctn.gif

7. Mirrors are normally used to demonstrate reflection because their shiny flat surfaces produce regular reflection. They reflect light in a regular and predictable way.

8. The reflection of light in a plane mirror enables us to see our own image in the mirror.

9. The image in a plane mirror is
(a) virtual (cannot be formed on a screen)
(b) upright
(c) laterally inverted
(d) the same size as the object
(e) the same distance behind the mirror as the object is in front.


Law Zhi Yang

Reflection of Light
- It occurs when light bounces off the surface of an object
- When light travels from a medium of lower density to a medium or higher density, the speed of light decreases.
- Law of reflecction: When a ray of light reflects off a surface, the angle of incidence is equal to the angle of reflection, and the incident ray,normal and refrlected ray is on the same plane.- http://www.tau.ac.il/~phchlab/experiments/Sucrose/reflpar.gif

Refraction of Light
- It is the bending of a light ray when it enters a medium of different density.
Law of refraction: The ratio of the sine of the angle of incidence and the sine of the refraction of a wava are constant when it passes between two given media.
http://www.dkimages.com/discover/previews/889/65018453.JPG


Muhamad Izzwan Emir bin Muhamad Azmi

Reflection of Light

1. Reflection is the bouncing of light from the surface of an object.
2. When the reflected light enters our eyes , we can see object.
3. The reflection of light depends on the nature of surface reflecting it.
a) When a parallel beam of light hits a smooth surface such as mirror or glass , a regular reflection is produced.

external image reflection.gif

b) When a parallel beam of light hits on a rough surface such as sand paper or wood , it is scattered. A diffused reflection is produced.

external image reflection1.gif



Natasha Iman binti Mohd Azri Periasamy


Philip Ooi Jun Qiang



The Law's
1.The Law of reflection states that when a ray of light reflects off a surface,the angle of incidence is equal to the angle of reflection and the incident,normal and reflected ray is on the same plane.

optical-illusion.jpg

The image appears to be moving.

Refraction
~Refraction of light is the bending of a light ray when it enters a medium of different density.
~The Law of Refraction states that the ratio of the sine of the angle of incidence and the sine of the angle of refraction of a wave are constant when it passes between two given media.
refraction.gif


Putri Nur Diyana binti Abdul Rashid


Defects of vision

Short-sightedness

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  • Short-sightedness is also known as myopia.
  • A short-sighted person can see near objects but cannot see distant objects.
  • Light from a distant object is focused in front of the retina.
  • People has short-sightedness because their lens is too thick or their eyeball is too long.
  • Short-sightedness can be corrected using a concave lens because it will diverge the light ray so that the image will form on the retina.

Long-sightedness

Long-sightedness.gif


  • Long-sightedness is also known as hyperopia or hypermetropia.
  • A long-sighted person can see distant objects but cannot see near objects.
  • Light from a near object is focused behind the retina.
  • People has long-sightedness because their lens is too thin or their eyeball is too short.
  • Long-sightedness can be corrected a convex lens because it will converge the light ray so that the image will form on the retina.


Types of vision

Stereoscopic vision

Stereoscopic_Vision.jpg


  • Animals with stereoscopic vision have both eyes at the front of the head.
  • The visual fields of animals with stereoscopic vision of both eyes overlap.
  • Animals with stereoscopic vision can see images three dimensionally, which helps to judge distances accurately.
  • The field of vision of animals with stereoscopic vision is narrow.
  • Predators such as lions, owls and dogs usually have stereoscopic vision.

Monocular vision

Monocular_Vision.jpg


  • Animals with monocular vision have eyes at the side of the head.
  • The visual fields of animals with monocular vision have little or no overlapping.
  • Animals with monocular vision can see images two dimensionally, which helps to detect enemies from a wide range of directions.
  • The field of vision of animals with monocular vision is wide.
  • Prey such as fishes, rabbits and grasshoppers usually have monocular vision.


Robin Lee Wei-Ern

Astigmatism
One of the defects of the eye is astigmatism. Astigmatism happens when an optical system has different foci for rays that propagate in two perpendicular planes. If an optical system with astigmatism is used to form an image of a cross, the vertical and horizontal lines will be in sharp focus at two different distances.

Forms of astigmatism

Astigmatism
Astigmatism
external image magnify-clip.png Astigmatism
1.There are two distinct forms of astigmatism.
a)The first is a third-order aberration, which occurs for objects (or parts of objects) away from the optical axis.

b)This form of aberration occurs even when the optical system is perfectly symmetrical. This is often referred to as a "monochromatic aberration", because it occurs even for light of a single wavelength.

2.The second form of astigmatism occurs when the optical system is not symmetric about the optical axis.
a)This may be by design (as in the case of a cylindrical lens), or due to manufacturing error in the surfaces of the components or misalignment of the components.

b)In this case, astigmatism is observed even for rays from on-axis object points.

c)This form of astigmatism is extremely important in opthalmology, since the human eye often exhibits this aberration due to imperfections in the shape of the cornea or the lens.

To test your vision, place the chart in a well illuminated area and stand 6 meters (or about 20 feet) from the chart. Test one eye at a time. If you see lines of grey and others black, you have an astigmatism.

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external image BARASTIG.GIF
ASTIGMATISM'S TEST . Close one eye and then the other one , if you do not see all the lined squares, in the same black color , if you do see one or more squares grey, you than have an astigmatism. ASK FOR A SPECIALIST ADVICE !!!

Optical illusions

1.An optical illusion (also called a visual illusion) is characterized by visually perceived images that are deceptive or misleading.

2.The information gathered by the eye is processed by the brain to give a percept that does not tally with a physical measurement of the stimulus source.

3.There are two main types of illusion - cognitive illusions and physiological illusions that are the effects on the eyes and brain of excessive stimulation of a specific type - brightness, tilt, color, movement, and cognitive illusions where the eye and brain make unconscious inferences.

Optical Illusion Gallery



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Stare at the blue circle in the center. The entire circle appears to be radiating.


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This picture depicts the impossible square and the impossible triangle.

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This picture appears to bulge but consists of only straight lines.

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The flow of water looks kind of impossible.

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The circles appear to be rotating.

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Mirror or Skull?

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Which of the circles in the center appear bigger?

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Upside down?

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Move your head back and forth while staring at the circle in the center. The outer rings will appear to move.

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Two horses and a few birds or a woman?

Total Internal Reflection

1. When light passes from one medium into a second, less dense medium, the light bends away from the normal.

2. At a particular incident angle, the angle of refraction will be 90 degrees, and the refracted ray would travel along the boundary between the two media.

3. The incident angle at which this occurs is called the critical angle.

4. This angle can be calculated by using Snell's Law:


sin(criticle angle) = (n2/n1)(sin 90 degrees) = (n2/n1)
Where n1 = index of refraction in 1st medium

n2 = index of refraction in 2nd medium



5. If the angle of incidence is increased beyond the critical angle, the light rays will be totally reflected back into the incident medium.

6. This effect is called total internal reflection. But note that total internal reflection cannot occur if light is traveling from a less dense medium to a denser one.
external image critical_angle.gif























1. Diamonds achieve their brilliance partially from total internal reflection.

2. Because diamonds have a high index of refraction (about 2.3), the critical angle for the total internal reflection is only about 25 degrees.

3. Incident light therefore strikes many of the internal surfaces before it strikes one less than 25 degrees and emerges. After many such reflections, the colors in the light are separated, and seen individually.
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Fiber optics

1. In the late 20th century, a new, practical application of total reflection was found in the use of fiber optics.

2. If light enters a solid glass or plastic tube obliquely, the light can be totally reflected at the boundary of the tube and, after a number of successive total reflections, emerge from the other end.

3. The reflective properties of fiber optic strands make fiber optic cables more efficient than cables that transmit signals electrically.

4. The flexible bundles, which can be used to provide illumination as well as to transmit images, are valuable in medical examination, as they can be inserted into various openings.
external image optical_fibers.jpg

EXTRA INFO:

Hearts And Arrows Diamonds


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Hearts and arrows diamond bezel, star, upper girdle, lower girdle, and pavilion main facets must be aligned precisely 180 degrees opposite of each other or the "H&A" pattern will be incomplete, misalign, faded or distorted in its appearance.All the facets must be exactly the same shape and size. If the cut of the diamond is even slightly asymmetric, it results in, uneven or incomplete display of the pattern.


Roy Tang Kah Chun


200px-Refraction-with-soda-straw.jpg
Refraction is the change in direction of a wave due to a change in its speed. This is most commonly seen when a wave passes from one medium to another. Refraction of light is the most commonly seen example, but any type of wave can refract when it interacts with a medium, for example when sound waves pass from one medium into another or when water waves move into water of a different depth.

Explanation
In optics, refraction occurs when light waves travel from a medium with a given refractive index to a medium with another. At the boundary between the media, the wave's phase velocity is altered, it changes direction, and its wavelength increases or decreases but its frequency remains constant. For example, a light ray will refract as it enters and leaves glass; understanding of this concept led to the invention of lenses and the refracting telescope.


Syarifah Aminah Ibrahim

<font face="trebuchet ms" size="6" color="red">Total Internal Reflection</font>

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Figure above represents total internal reflection.

1. optical phenomenon that occurs when a ray of light strikes a medium boundary at an angle larger than the critical angle with respect to the normal to the surface.
2. If the refractive index is lower on the other side of the boundary no light can pass through, so effectively all of the light is reflected. 3.The critical angle is the angle of incidence above which the total internal reflection occurs.

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The larger the angle to the normal, the smaller is the fraction of light transmitted, until the angle when total internal reflection occurs.

Total internal reflection occurs in diamonds.
diamonds.jpg



Teoh Jun Vinh

Defects of Vision

Near-sightedness (also called Myopia)
Nearsightedness or Myopia is the inability of the eye to 'see' or focus on objects that are of a considerable distance. It has no problem seeing near objects, though. The eye needs light to be refracted less to see distant objects. If the light is refracted more than necessary, this will result in near-sightedness.

Near-sightedness most frequently happens at a young age. Most of the time, near-sightedness happens as a result of:

i. The cornea is too big
- If the cornea is too big, it will refract light more than usual. This causes the images of distant objects to form too far away from the retina, thus the image is not focused on the retina, and making it seem blurry.

ii. The eyeball is too long
If the eyeball is too long, the retina is then placed further from the cornea and/or lens. This produces the same results as what happens if the cornea is too big.

external image 1.gif
Correction of Near-sightedness
Because the problem of near-sightedness is 'the image forms too far away or in front of the retina', a concave lens is used to diverge light before the lens and/or cornea converges the light, thus effectively focusing the image on the retina.
external image 2.gif

Example of Near Sightedness:
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Far-sightedness (also called Hyperopia)
Far-sightedness or Hyperopia is the inability of the eye to see near objects. The opposite of near-sightedness, it has no problems seeing distant or far objects.
To view near objects, the eye needs a different lens shape, which the far-sighted eye cannot assume, thus rendering it unable to view nearby objects.

Also unlike Myopia, Hyperopia generally arises during the older stages in life, mainly the result of:

i. The weakening of the ciliary muscles
ii. The decreased flexibility of the lens.

To view near objects, light needs to be refracted more. The two conditions above results in the eye being less capable of refracting light, and the image is formed behind the retina. This makes the object seem blurry.
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Correction of Far-Sightedness
To help the eye see distant objects, a convex lens is used to help the lens refract the light more, thus focusing the image onto the retina instead of behind it.
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Example of Far-Sightedness:
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Tio Shu Anne

1.7 Light and Sight
The Properties of Light
-Light travels in a straight line
-Light travels at the speed of 300000000 m/s in vacuum
-Light can be reflected
-Light can be refracted

Reflection and Refraction of Light
Untitled1.png
Reflection of Light
Reflection of light occurs when light bounces off the surface of an object.

The law of reflection states that when a ray of light reflects off a surface the angle of incidence is equal to the angle of reflection and the incident ray, normal and the reflected ray is on the same plane.
Untitled2.png
Light can travel through transparent media (air, water, glass and plastic)

Refraction of Light
Refraction of light occurs when light travels from one medium to another (the speed of light changes). When light enters a medium of different density, the light ray bends.

The law of refraction states that the ratio of sine of the angle of incidence and the sine of the angle of refraction of a wave are constant when it passes between two given media
Untitled3.png
When light travels from a medium of lower density to a medium of higher density the speed of light decreases. The light is refracted towards the normal.

When light travels from a medium of higher density to a medium of lower density the speed of light increases. The light is refracted away from the normal.


Wong Qi-Shaun

properties of light.
1. light travels in a straight line ( completely absolute)
2. can be refracted and reflected
3. travels at the speed of 300000000 meters per second in vacuum
( may differ on earth as different densities will influence the speed of the light)

refraction.
1. makes a spoon appear bend in water 200px-Refraction-with-soda-straw.jpg
2. makes fish seem much closer to the surface of water

reflection
1. as light passes down onto earth, shiny objects, will reflect light.
2. a smooth shiny surface will easily reflect light
3. a dull rough surface will still reflect light but rather poorly.images.jpeg

note: diamonds
diamonds sparkle because of total internal reflection where when light goes through the diamond, it reflects the same way the light came in therefore producing a bright sparkle

long sightedness.
occurs when the eyeball is too short and the lens is too thin
can see images from afar but have difficulty seeing the images from near.IMAGE_00395.jpg
see, the image looks blur because the lens is too thin, therefore the object that can be seen from far will not be blur
can be corrected with concave lens

short sightedness
occurs when the eyeball is too long and the lens is too thick
can see images from near but have difficulty seeing object from afar

IMAGE_00393.jpg
the image appears blur from far as the lens is too thick
can be corrected using convex lens


Woon Tyen How

Properties of light
• Light travels in a straight line.
• Can be reflected, refracted.
• Travels at the speed of 300,000,000 m/s in vacuum.
• Light can experience interference.
• Light is an electromagnetic wave.


Reflection

• Reflection occurs when light bounces off the surface of an object.
• Shiny, smooth and flat surfaces produce a regular reflection.
• Dull, rough and irregular surfaces produce an diffuse reflection.

755px-MtHood_TrilliumLake.jpg

This picture shows the reflection of the mountain in the lake.

Law of Reflection

• When a ray of light reflects off a surface, the angle of incidence is equal to angle of reflection, and the incident ray, normal and reflected ray is on the same plane.

Refraction

• Light can travel through transparent media such as air, water, glass and plastic.
• When light travels from a lower density to a higher density, the speed of light decreases, and vice versa.
• The decreasing or increasing of the speed of light causes the light to bend/change direction.
• This bending is known as refraction.

sci_ill1straw.jpg

This picture shows the straw bended due to the refraction of light.

Other phenomenas include fishes appearing closer to the surface of a pond that it is, and a pool seeming shallower.

Law of Refraction (Snell's Law)

• The ratio of the sine of the angle of incidence and the sine of the angle of refraction of a wave are constant when it passes between two mediums of different densities.

Extra info:
Diamonds sparkle because they reflect light falling on them. This is called total internal reflection.





Yau Ga Luoh