This book is not a story. This book is a study book for those who likes to study science. I put this way for those who are so lazy to study in their actual books. So, yeah. Hope this book helps you for your knowledge about science.
Actually, the les...
1 (a) A person with normal vision sees distant and close objects clearly. (b) The thickness of the eye lens changes when near or distant objects are focused. (c) This process is known as accommodation.
2 The common defects of vision are ◆ short-sightedness ◆ long-sightedness ◆ astigmatism ◆ colour blindness ◆ presbyopia
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Okay. So let's take a recap!
1.7 Light and sight
Reflection of light
Reflection of light takes place when light rays fall on the surface of an opaque object and bounce off it.
Example:
A student looking at his image on the surface of a lake. The formation of an image in a mirror is another example of light reflection.
The amount and direction of the reflected light depend on the type of the surface the light falls on. Plane mirrors and shiny metals are good light reflectors because they have smooth and flat surfaces.
Regular reflection ➡ When a flat and smooth surface like a mirror reflects light in a regular pattern.
Diffused reflection ➡ When light falls on irregular surfaces like paper and cloth, the reflected light rays are scattered in different directions.
When light strikes a smooth reflecting surface (for example, a mirror) at an angle to the normal, it is reflected at the same angle on the opposite side of the normal.
☆ Application of the reflected of the light
1. Periscopes ➡ are used in submarines to observe objects outside the submarine.
2. Kaleidoscope ➡ forms beautiful images when pieces of paper of various colours are put inside it.
3. Mirror ➡ used by a dentist when examining a patient's teeth.
Refraction of light
The refraction of light is the bending of light as it passes from one transparent medium to another. This happens when light travels through different media such as air, water and glass.
The refraction of light occurs when the speed of light changes. This happens when light travels through two types of media that have different densities.
The speed of light decreases when light enters a denser medium, for example, from air to glass.
It increases when light enters a less dense medium, for example, from glass to air.
When light travels at an angle from a less dense medium to a denser medium, it is refractedtowards the normal.
When light travels from a dense medium to a less dense medium, it is refracted away from the normal.
☆ Phenomena of the refraction of light
The pond appears to be shallower than it really is.
Light from the bottom of the pond is refracted away from the normal. This happens when light emerges from the water into the air because light travels faster in air than in water.
The refracted light enters the eye of the observer. The observer sees an image of the 'bottom of the pond' somewhere above the pond's bottom.
So, the pond appears to be shallower than it really is.
The drinking straw in the glass of water appears to be bent.
When light from the straw travels from the water to the air, light is refracted away from the normal.
The light enters the eye of the observer. The observer sees the image of the straw somewhere above the bottom of the glass.
Thus, the straw appears bent.
The dispersion of white light into its seven component colours of the rainbow is a phenomenon of light refraction.
Light refraction allows images to be formed on the retina of the eye.
Lenses that refract light are used as magnifying glasses and in telescopes, microscopes and spectacles.
Vision defects and ways to correct them
A person with normal vision sees distant and close objects clearly. The thickness of the eye lens changes when near or distant objects are focused. This process is known as accommodation.
The common defects of vision are ◆ short-sightedness ◆ long-sightedness ◆ astigmatism ◆ colour blindness ◆ presbyopia
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Hey guys! Sarreh for not updating so long. Because this lesson is just toooooo long so yeah. There is a part 2 of this. So just stay tune! 😊
![Learn Science [Form 2]](https://img.wattpad.com/cover/71194143-64-k150233.jpg)