17555704
Descrição
Mapa Mental por Emily Chase, atualizado more than 1 year ago
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Criado por Emily Chase
mais de 5 anos atrás
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Light and the Electromagnetic Spectrum
- CP5a
- We see things when light travels
from a source and is reflected by
an object into out eyes.
- The light transfers energy
from the source to our eyes
- Our eyes can detect
certain frequiencies of
light
- We refer to these
frequencies as visible light
- We refer to these
frequencies as visible light
- The light transfers energy
from the source to our eyes
- Light is a type of electromagnetic wave
- Different frequencies cause us to
see different colours
- Lower frequencies of visible light appear more
red and higher frequencies appear more blue
- Lower frequencies of visible light appear more
red and higher frequencies appear more blue
- All electromagnetic waves
are transverse waves
- Because electromagnetic waves are
transverse this means the vibrations
are at right angles to the direction in
which the wave is travelling
- All electromagnetic waves travel at the same speed:
(3 x 10 to the power of 8 m/s)
- All electromagnetic waves travel at the same speed:
(3 x 10 to the power of 8 m/s)
- Like all waves, electromagnetic waves transfer
energy from a source to an observer
- Electromagnetic waves with frequencies slightly
lower than visible light are called infrared
- All objects emit energy by
infrared radiation
- We can feel the effects of infrared radiation when energy is
transferred from the Sun to our skin
- All objects emit energy by
infrared radiation
- Electromagnetic waves move at different speeds in
different materials
- Waves that pass at an interface (boundary) between two
materials get faster or slower
- If waves meet an interface (boundary) at
an angle the change of speed also makes
them change direction
- The change of direction is called refraction
- If they meet the interface (boundary) at right angles they
do not change direction
- The change of direction is called refraction
- Waves that pass at an interface (boundary) between two
materials get faster or slower
- The first person to discover infrared
was William Herschel
- He put dark coloured filters on his telescope to
help him observe the sun safely and noticed
that different coloured filters heated the
telescope to different extents
- He put dark coloured filters on his telescope to
help him observe the sun safely and noticed
that different coloured filters heated the
telescope to different extents
- We see things when light travels
from a source and is reflected by
an object into out eyes.
- CP5b
- Our eyes can detect different colours in
visible light and scientists describe the
seven colurs in the visible light
spectrum in this order:
- Red, orange, yellow, green, blue, indigo, violet
(ROY G BIV)
- Red, orange, yellow, green, blue, indigo, violet
(ROY G BIV)
- If the frequency of a wave is lower than that of
red light, human eyes cannot see it
- Infrared, microwaves and radio
waves have lower frequencies than
red light
- Ultraviolet light has a higher
frequency than visible light
- Even higher frequencies and shorter wavelengths are
present in x-rays and gamma rays
- Even higher frequencies and shorter wavelengths are
present in x-rays and gamma rays
- Infrared, microwaves and radio
waves have lower frequencies than
red light
- The full range of
electromagnetic waves is called
the electromagnetic spectrum
- The spectrum is continuous so all values
of frequency are possible
- Higher frequency waves have shorter
wavelengths and lower frequency waves
have longer wavelengths
- Higher frequency waves have shorter
wavelengths and lower frequency waves
have longer wavelengths
- The spectrum is continuous so all values
of frequency are possible
- Stars and other space objects can
emit energy at all wavelengths.
- Scientists study this radiation but have to use
special telescopes because different materials
affect electromagnetic waves depending on the
wavelength
- Scientists study this radiation but have to use
special telescopes because different materials
affect electromagnetic waves depending on the
wavelength
- Our eyes can detect different colours in
visible light and scientists describe the
seven colurs in the visible light
spectrum in this order:
- CP5c
- Visible light is the part of the
electromagnetic spectrum that our eyes
detect
- Light bulbs are designed to emit visible light, while
cameras detect it and record images
- Light bulbs are designed to emit visible light, while
cameras detect it and record images
- Infrared radiation can be used for
communication at short ranges
- Infrared can be used between computers in the
same room or from a TV to its remote control
unit
- Information sent along optical fibres is also
sent using infrared radiation
- A grill or toaster transfers energy
to food by infrared radiation
- The food absorbs the
radiation and heats up
- The food absorbs the
radiation and heats up
- Information sent along optical fibres is also
sent using infrared radiation
- Infrared can be used between computers in the
same room or from a TV to its remote control
unit
- Thermal images show the amount
of infrared radiation given off by
different objects
- Security systems often have sensors that can
detect infrared radiation emitted by intruders
- Some buildings are fitted with systems of infrared beams
and detectors and when someone walks through one of
the beams will break it and set off an alarm
- Some buildings are fitted with systems of infrared beams
and detectors and when someone walks through one of
the beams will break it and set off an alarm
- Security systems often have sensors that can
detect infrared radiation emitted by intruders
- Microwaves are used for communications and satellite
transmissions, including mobile phone signals
- In a microwave oven,
microwaves transfer energy
to the food, heating it up from
the inside
- In a microwave oven,
microwaves transfer energy
to the food, heating it up from
the inside
- Radio waves are used for transmitting radio broadcasts and
TV programs as well as other communications
- Some radio waves are sent via satellites so
controllers on the ground communicate with
spacecraft suing radio waves
- Radio waves are produced by
oscillations (variations in a current
and voltage) in electrical circuits
- A metal rod can be
used as an aerial to
receive radio waves
- Waves travel in straight lines unless they
are reflected or refracted
- Waves travel in straight lines unless they
are reflected or refracted
- A metal rod can be
used as an aerial to
receive radio waves
- Some radio waves are sent via satellites so
controllers on the ground communicate with
spacecraft suing radio waves
- Visible light is the part of the
electromagnetic spectrum that our eyes
detect
- CP5d
- Ultraviolet radiation transfers
more energy than visible light
- It is absorbed by most of the same materials that
absorb visible light, including our skin
- The energy transferred can be used to
disinfect water by killing microorganisms
in it
- The energy transferred can be used to
disinfect water by killing microorganisms
in it
- Some materials absorb ultraviolet light and
re-emit it as visible light, this is called florescence
- Fluorescent materials are often only used in security markings
- they are only visible when ultraviolet light shines on them
- Fluorescent materials are often only used in security markings
- they are only visible when ultraviolet light shines on them
- It is absorbed by most of the same materials that
absorb visible light, including our skin
- Ultraviolet radiation transfers
more energy than visible light
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