Transcript The Electromagnet Spectrum - singhscience

Starter
The Electromagnetic
Spectrum
Learning Objectives
• I must be able to state that all
electromagnetic waves are transverse.
• I should be able to describe the
electromagnetic spectrum.
• I might be able to explain differences n
wavelength and frequencies of waves within
the electromagnetic spectrum.
P1.7 Infrared, visible and
ultraviolet
The Tarantula Nebula photographed by the Hubble Space
Telescope in visible light, infrared and ultraviolet.
Invisible Light
The Electromagnetic Spectrum
Electromagnetic Spectrum
• Visible light, infrared, ultraviolet radiation
are all types of electromagnetic radiation.
• The waves transfer energy from one place
to another and can travel through a
vacuum.
• Electromagnetic vibrations travel at right
angles to the direction of energy
transferred by waves. They are therefore
transverse waves.
The Electromagnetic Spectrum
Wavelength and Frequency
• Electromagnetic waves that have
long wavelengths have short
frequencies.
• And electromagnetic waves that
have short wavelengths have long
frequencies.
Task 2
• Complete worksheet 1.7b.
Electromagnetic Spectrum
• A full range of electromagnetic
waves is called the electromagnetic
spectrum.
• It is like a bigger version of the visible
spectrum that includes wavelengths
of light that we cannot see.
Task 3
• Complete worksheet 1.7c.
Can you think of an easy
way to remember…
From the shortest wavelength to the longest.
• Gamma rays
• X-rays
• Ultraviolet rays
• Visible light
• Infrared
• Microwaves
• Radio waves
740nm
370nm
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Wavelength: 1m to 100000m
Frequency: 3 x 109 to 3 x 104 Hz
Uses: Telecommunications, TV, Radio
Dangers: none
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Wavelength: 0.001m to 1m
Frequency: 3 x 1012 to 3 x 109 Hz
Uses: Telecommunications, RADAR, Cooking
Dangers: can produce burns, cataracts, cancer (?)
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Wavelength: 740nm to 0.01m
Frequency: 4 x 1014 to 3 x 1011 Hz
Uses: Heating, cooking, TV remotes, night-vision
Dangers: can burn
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Wavelength: 370nm (violet) to 740nm (red)
Frequency: 8 x 1014 to 4 x 1014 Hz
Uses: seeing
Dangers: eye damage from bright lights
Visible light is best at
getting through our
atmosphere – which is
why we use it to see!
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Wavelength: 10-9 m to 370nm
Frequency: 3 x 1017 to 8 x 1014 Hz
Uses: discos, tanning salons, counterfeit detections, pollination
Dangers: skin cancer
Bees see in UV to
help them find
pollen!
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Wavelength: 10-12 to 10-7 m
Frequency: 3 x 1020 to 3 x 1015 Hz
Uses: medical imagery, security
Dangers: cancer
Hand with Rings by Wilhelm Röntgen.
The first "medical" X-ray of his wife's hand
taken on 22 December 1895.
()
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Wavelength: 10-16 to 10-9 m
Frequency: 3 x 1024 to 3 x 1017 Hz
Uses: cancer treatment, observing the universe
Dangers: cancer
The Dangers of the EM Spectrum
As the wavelength of EM spectrum changes, the way the different
wavelengths interact with matter also changes.
As the frequency increases, wavelength gets smaller. Eventually the
waves are so small that they can interact with cells, DNA and atoms. This
is called IONISING RADIATION.
NON-IONISING
IONISING