5. Description of
EM Spectrum
The electromagnetic
spectrum is the
range of frequencies
of electromagnetic
radiation and their
respective
wavelengths and
photon energies.
– wikipedia
6. Description of EM Spectrum
The electromagnetic spectrum is a continuum
of electromagnetic waves arranged according
to frequency and wavelength. It is a gradual
progression from the waves of lowest
frequencies to the waves of highest
frequencies. According to increasing
frequency, the EM spectrum includes: radio
waves, microwaves, infrared, visible light,
ultraviolet, X-rays, and gamma rays. These
waves do not have exact dividing region.
7. USES OF
EM SPECTRUM
Electromagnetic waves have a vast
range of practical everyday
applications that includes such
diverse uses as communication by
cell phone and radio broadcasting,
WiFi, cooking, vision, medical
imaging, and treating cancer.
8. Because Gamma rays can kill
living cells, they are used to kill
cancer cells without having to
resort to difficult surgery. This is
called "Radiotherapy", and
works because healthy cells can
repair themselves fairly well
when damaged by gamma rays -
but cancer cells can't.
EM Spectrum
in Treating
Cancer
9. ●Electromagnetic radiation includes everything from gamma rays to
visible light to radio waves. Your laptop/tablet/etc. uses a
wireless adapter to translate data into a radio signal and
transmit that signal using an antenna. Those radio waves emanate
outwards from the antenna and are received by your wireless
router.
EM Spectrum on Wireless Connections
10. EMR has very beneficial uses
of our daily life to make it
more comfortable and easier.
Nowadays, we can talk to
anyone on a mobile phone
through the Internet: it is
because of EMR, since these
waves can transmit signals for
very long distances. So EMR
has the key roles in making
our lives more comfortable.-
Over-exposure to certain types of
electromagnetic radiation can be harmful. The
higher the frequency of the radiation, the
more damage it is likely to cause to the body:
microwaves cause internal heating of body
tissues. Infrared radiation is felt as heat and
causes skin to burn.
EM SPECTRUM
ADVANTAGES DISADVANTAGES
11. Frequency and wavelength are
inversely proportional to each
other. The wave with the
greatest frequency has the
shortest wavelength. Twice the
frequency means one-half the
wavelength. For this reason, the
wavelength ratio is the inverse
of the frequency ratio.
Frequency and
Wavelength
14. In the year 1800, Sir William Herschel
was exploring the question of how much
heat was contained by the different
colors of visible light. He devised and
experiment where he used a glass
prism to separate sunlight into it's
rainbow of colors. Then, he placed a
thermometer under each color, with one
extra thermometer just beyond the red
light of the spectrum. He found that the
thermometer that was seemingly out of
the light had the highest temperature.
Thus, he discovered infrared light.
15. Infrared waves, or infrared
light, are part of the
electromagnetic spectrum.
People encounter Infrared
waves every day; the human
eye cannot see it, but humans
can detect it as heat. A remote
control uses light waves just
beyond the visible spectrum of
light—infrared light waves—to
change channels on your TV.
Infrared
Light
16. Characteristics of
Infrared Lights
Infrared waves have longer wavelengths than
visible light and can pass through dense
regions of gas and dust in space with less
scattering and absorption. Thus, infrared
energy can also reveal objects in the
universe that cannot be seen in visible light
using optical telescopes.
17. Uses of Infrared Light
Infrared radiation can promote local blood circulation and
reduce muscle tension. Examples of traditional medical
applications of infrared radiation include the relief of
muscle pain and tension, as well as the treatment of
autoimmune diseases or wound-healing disorders.
18. ADVANTAGE OF
INFRARED LIGHT
Infrared therapy has many roles in the
human body. These include
detoxification, pain relief, reduction of
muscle tension, relaxation, improved
circulation, weight loss, skin
purification, lowered side effects of
diabetes, boosting of the immune
system and lowering of blood pressure.
19. DISADVANTAGE OF
INFRARED LIGHT
Prolonged exposure to IR radiation
causes a gradual but irreversible
opacity of the lens. Other forms of
damage to the eye from IR exposure
include scotoma, which is a loss of
vision due to the damage to the retina.
Even low-level IR absorption can
cause symptoms such as redness of
the eye, swelling, or hemorrhaging.
21. This range in wavelengths in
the Visible Light Spectrum
was discovered by Isaac
Newton in the 17th century,
although there is further
knowledge that it had been
discovered four centuries
earlier in the 13th century
by Roger Bacon. Visible light
is the only part of the
Electromagnetic Spectrum
humans can detect.
22. It was discovered by Isaac Newton in 1665
by taking Roger Bacon's discovery of
visible light by looking through a glass of
water, a little farther as he tried the
experiment more and finally wrote his
thoughts down about the rainbow colors he
saw through a prism. In 1665, Isaac
Newton, then a young scientist at
Cambridge University in England, took a
glass prism and held it up to a beam of
sunlight streaming through the window. He
saw the sunlight that passed through the
prism spread out into the colors of the
rainbow - red, orange, yellow, green, blue
and violet.
23.
24. ● Light or "visible light" refers to the visible region of the electromagnetic
spectrum – that is, the range of wavelengths that trigger brightness and colour
perception in humans. It lies between UV and infrared radiation.
● Some other sources of visible light include: television and computer screens,
glow sticks, and fireworks.
Visible Light
25. The most important characteristics of visible light are colour which is
both an inherent property of light and an artifact of the human eye. Our
eyes include specialized cells known as cones. These cones act as
receivers that are tuned to the wavelength of the narrowband of the EM
spectrum.
Characteristic of Visible Light
26.
27. Visible light is the light we can see, so is used in
photography and illumination. It is also used in fibre optic
communications, where coded pulses of light travel through
glass fibres from a source to a receiver.
Uses of Visible Light
28. Visible Light in Optic Communication
● Visible light sources are now being used in this
field, bringing advantages in both visibility and
workability. In particular, current trends and
subjects affecting the key devices used in these
networks, such as visible light sources, optical
fibers, optical circuits and transceiver modules, are
explained.
● coded pulses of light travel through glass fibres
from a source to a receiver.
29.
30. Visible Light in Photography and Illumination
● Visible cameras utilize wavelengths of light from
400~700nm, which is the same spectrum that the
human eye perceives. Visible cameras are designed
to create images that replicate human vision,
capturing light in red, green and blue wavelengths
(RGB) for accurate color representation.
31. Visible Light in Photosynthesis
● Light energy enters the process of photosynthesis when
pigments absorb the light. In plants, pigment molecules
absorb only visible light for photosynthesis. The visible
light seen by humans as white light actually exists in a
rainbow of colors.
32. ADVANTAGE OF
VISIBLE LIGHT
Along with the given uses
which are Visible Light’s
advantage, Visible light
helps humans to see, this is
the most important
advantage of visible light.
33. DISADVANTAGE OF
VISIBLE LIGHT
Visible light is essential for the
perception and appreciation of art, but it,
too, contributes to degradation and
damage of objects. Irreversible damage
caused by light can include color fading,
yellowing, and embrittlement.
Overexposure to visible light could harm
the human eyes, some materials could
undergo deterioration due to chemical
changes.