Electromagnetic Waves: Visible Light, UV and X-rays

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  • Created by: Go
  • Created on: 24-12-12 19:13
What do we need visible light for?
To see.
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Why do we see objects?
We only see objects because they're illuminated - they either give out or reflect light.
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To see an object...
Light needs to enter our eyes.
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How do we see light?
When light enter your eye, it gets refracted through the lens and focused onto the retina at the back of your eye. The retina then sends messages to the brain (via the optic nerve), and the brain interprets them - then you can see.
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How does photography work.
Cameras use a lens to focus visible light onto a light-sensistive film or electronic sensor that records the image.
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What is a property of certain chemicals, where ultraviolet radiation (UV) is absorbed and then visible light is emitted (i.e produced).
Fluorescence
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Nowadays they'll print special markings in fluorescent ink on bank notes to do what?
To detect whether it is genuine or fake. Under UV light, genuine notes will display the special fluroescent marking. Whereas when fake notes are placed under UV light they'll glow all over, and they'll be no markings.
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In detecting forged bank notes, it's the amount of radiation _____ that your _____ and _____.
In detecting forged bank notes, it's the amount of radiation emitted that you're detecting and measuring.
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Why do fluorescent colours look so bright?
Fluorescence is a property of certain chemicals, where ultraviolet radiation (UV) is absorbed and then visible light is emitted (i.e produced).
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Why are fluroescent lamps safe to use?
Because all of the UV radiation is absorbed by a phosphor coating on the inside of the glass.
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What does security pens use?
Ultraviolet radiation: the ink in the pen is only visible in UV light - this can help the police identify your property if it's stolen.
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When disinfecting water, what should you use?
UV radiation: the ultraviolet kills off any viruses and bacteria in the water.
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Where may you use X-rays.
To take X-ray 'photographs' of people to see if they have any broken bones.
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X-rays pass easily through flesh, but do they pass just as easily through denser materials such as bones or metal?
No
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X-rays pass easily through flesh but not so easily through denser material like bones or metal. So it's the amount of radiation that's _____ (or not _____) that gives you and X-ray image.
Absorbed
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What does airport security use to scan luggage to check for suspicious looking objects?
X-rays
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X-rays can cause cancer, so radiographers wear _____ aprons and stand behind a _____ screen or leave the room to keep their exposure to X-rays to a minimum
Lead
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Other cards in this set

Card 2

Front

Why do we see objects?

Back

We only see objects because they're illuminated - they either give out or reflect light.

Card 3

Front

To see an object...

Back

Preview of the front of card 3

Card 4

Front

How do we see light?

Back

Preview of the front of card 4

Card 5

Front

How does photography work.

Back

Preview of the front of card 5
View more cards

Comments

epster

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good quiz !!!

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