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25 Cards in this Set
- Front
- Back
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What type of form is light? |
Light is a form of energy called electromagnetic radiation. |
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How does it travel? |
It travels as a wave, called an electromagnetic wave. |
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How fast does light travel? |
300 000 km per second |
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What might happen when light hits a surface? |
It may be transmitted through it, reflected off it or absorbed into it. |
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Explain transparency and give examples. |
Transparency is when almost all light is transmitted through the substance. A clear image can be seen through it. Some examples are clear glass and shallow water. |
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Explain translucency and give examples. |
Translucency is when some light may be reflected, and light that passes through is scattered. An image seen through it is fuzzy. Some examples are tissue paper, fingernails, and frosted glass. |
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Explain opaque and give examples. |
Opaque is when light is either reflected from or absorbed into the substance, and no light is transmitted. No image can be seen through it. Some examples are a brick, a piece of wood, a desk and a football. |
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What is luminous? |
An object that releases or emits light is said to be luminous. |
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Do most objects around you produce their own light? |
No |
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What are they known as? What are some examples? |
Non-luminous, Moon |
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How do you see the light then? |
You see most of the things around you because light bounces off them and then into your eyes. This process is called reflection. |
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What is the Law of reflection? |
The law stating that light is reflected at the same angle that it is incident, or i = r |
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What is incident ray? |
Incoming ray. |
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What is the dotted imaginary line called? |
Normal |
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What is it used to measure? |
Angle of incidence= angle of reflection i=r |
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What is another name for plane mirror? |
Flat mirror |
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What is lateral inversion? |
The sideways or left-to-right reversal of an image in a plane mirror. |
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What is a plane mirror? |
Your image is identical to you in every way except that it is reversed sideways: your right side appears in the mirror as your left, and vice versa. |
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What is a virtual image? |
A type of image formed in which the rays of light do not actually meet, but only appear to meet at a point inside the mirror. |
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What does an image seen in a plane mirror look like? |
It is upright (normal way up), is the same size as the object, is laterally inverted (reversed sideways), is virtual and appears to be located as far inside the mirror as the object is in front. |
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What is refraction? |
The bending of light as it enters or leaves different substances. |
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How does light refract? |
Light refracts when it travels from one transparent substance into another. |
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Why does refraction occur? |
Light travels at different speeds through different substances. The differences in its speed result in different amounts of bending, or refraction, as light passes from one substance into another. |
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What is the refractive index? |
A measure of how easily light travels through a substance. |
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How does refractive index work? |
As light leaves a glass block, it speeds up and bends away from the normal. |
