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İHSAN DOĞRAMACI FOUNDATION
BİLKENT ERZURUM LABORATORY HIGH SCHOOL
2011-2012 ACADEMIC YEAR
PHYSICS TERM PROJECT
TOPIC: TYPES OF ELECTROMAGNETIC WAVES AND THEIR APPLICATIONS
PREPARED BY: RABİA HİZARCİ
SUBMITTED TO: MEHMET ALİ DOĞRU
INTRODUCTION
In this term project, my topic was investigating types of electromagnetic waves and their
applications. The reason why I chose this topic is that I wanted to learn more about EM waves
that we are exposed to everyday. My aims were:

Learning more about the general properties of electromagnetic waves,

Building up my knowledge about the types of electromagnetic waves and their main
differences,

Getting more information about the usage of EM waves in our daily lives

Getting aware of the most common harms of EM waves on humans,

Learning the ways of protecting ourselves from harmful radiation.
TYPES OF ELECTROMAGNETIC WAVES AND THEIR APPLICATIONS
Electromagnetic waves are transverse waves which consist of a combination of
oscillating electrical and magnetic fields, perpendicular to each other. Unlike other waves,
electromagnetic waves can travel both in the presence and absence of a medium. Despite not
carrying mass, they carry energy. They have momentum and besides, they can exert pressure
which is called radiation pressure. The speed of an electromagnetic wave in vacuum is equal
to c = 3.00 x 108 m/s , and it is calculated by the formulae “c = f × λ” where ‘f’ is the
frequency and ‘λ’ is wavelength.
There are different types of electromagnetic waves some of which are radio waves,
microwave, infrared, visible light, ultraviolet, X-ray and gamma rays. They are categorized
according to their frequency and shown in electromagnetic spectrum. Let us investigate these
wave types one by one:
Radio Waves
Radio waves are the result of charges accelerating through conducting wires. They are
generated by electronic devices like LC oscillator and they have a
wide range of wavelengths from 104 to 10-1 m. Due to their
relatively low frequency, they can be considered as one of the
harmless electromagnetic waves. As their name suggest, they are
generally used in radios, televisions, wireless networking and cell phones.
Microwaves
Microwaves are produced in molecular transitions from a high energy level to a lower energy
level. They have smaller wavelengths when compared to radio waves. For instance, hydrogen
gas emits microwave radiation with a wavelength of 21 cm.
Thanks to their smaller wavelengths they are suitable for
studying atomic and molecular properties of matter as well
as for radar systems. But they are generally known for their usage in microwave ovens. These
ovens cause vibration of food molecules. Thus, the vibrations warm the food. Moreover,
microwaves of lower frequencies are used by some of the cell phone networks.
Infrared
Having a range of wavelengths from 10-3 to 7 × 10-7 m, infrared waves were first detected by
Sir William Herschel and are emitted by many sources such as human body, hot pieces of
coal, light-bulb filaments and the sun. Also, it is produced in molecular transitions. These
waves are quickly absorbed by most materials. As electromagnetic waves carry energy, the
materials which absorb infrared waves gain internal energy due to rise in vibration. This
process results in increase in temperature. That’s why, infrared is popularly known as heat
radiation.
Infrared waves have a wide range of applications. As all the objects emit infrared radiation,
they cause a change in temperature around themselves.
Therefore, by using infrared sensors images of objects can be
produced. This is called thermography. Apart from imaging,
infrared is commonly used in heating. It is used for heating
saunas, heating food and cooking. Moreover, it is used when it
is needed to repair damaged asphalt. Besides, it is helpful to use IR in order to remove ice
from the wings of aircrafts. Other than these, IR is used for transmission of data in shortlengths, in digital cameras and in spectroscopy.
Visible Light
With a wavelength range from 400 nm to 700 nm, visible light is the only part of the
electromagnetic spectrum that can be detected by human-eye. Light can be produced either in
atomic transitions (as it is done in discharge tubes) or by accelerated electric charges (as it
occurs in hot filaments of lamps).
Frequency of light waves, decides on its color. For example, the one with the highest
frequency is detected as violet, whereas the one with lowest frequency is detected as red by
human eyes. When a white beam of light enters a glass prism, it is dispersed into its
constituent colors in an order of frequency:
Visible light enables us to see the objects. Apart from this, it is transmitted in optical fibers to
carry information which can be translated into sound or an image.
Ultraviolet
Ultraviolet radiation was first detected by Johann Ritter. It is a very energetic and ionizing
type of radiation. Its wavelength is between 4 × 10-7 and 6 ×10-10 m. Sun is the main source of
UV radiation, but ozone layer filters most of the UV radiation that is emitted by the sun. Due
to its high energy and ionizing effect, too much of UV is very harmful to human skin and eye.
That’s why sunglasses that filter UV radiation are needed to be used in order to protect
contraction of the pupils of eyes from UV radiation when you are exposed to direct sun light.
However, glasses that cannot filter UV radiation, but filters visible light instead, are much
more harmful than direct exposure to the sun
light. Because, when visible light is absorbed
instead of ultraviolet radiation, pupils of the eye
dilate and the lens is damaged. Apart from
sunglasses, sunscreen lotions must be used in
order to protect the skin from sunburns.
Otherwise, this situation might cause skin cancer.
Despite the fact that ultraviolet radiation gives harm to humans, it has a wide range of
applications. Firstly, it stimulates the production of vitamin D in the skin. Other than that, it is
used in fluorescent lamps, pest control, analyzing minerals, sterilization, spectrophotometry,
disinfecting drinking water, checking electrical insulation, food processing, fire detection and
photolithography.
X-Rays
As X-rays were discovered by Wilhelm Conrad Röntgen, these
waves are also known as Röntgen rays. They are produced
during the rapid deceleration of electron as a result of colliding
with atoms, or during the transition of elements from very
excited states to the ground state. As a very penetrating type of radiation, X-rays may cause
cancer and other damages in living tissues. That’s why direct exposure to X-rays must be
avoided. As a contradiction to causing cancer, they are used in the diagnosis and treatment of
cancer. Besides, they are used in revealing the details of bones and teeth, crystallography,
astronomy, microscopic analysis, fluorescence and in X-ray photographs.
Gamma Rays
Gamma rays, or γ-rays in other words, are the most energy rays with the highest frequency.
They are produced during radioactive decay and when particles annihilate in collisions with
their antiparticles. Since they are the most penetrating
rays when compared to the rest of the electromagnetic
waves, they cause the most severe harm such as DNA
alterations when absorbed by a living organism. That is
the reason why employees working near sources of gamma radiation wear thick layers of lead
in order to protect themselves.
In spite of being too harmful, it has benefits, too. For instance, they are used to sterilize
medical equipment as well as to remove decay-causing bacteria to make the freshness of
foods last longer. Moreover, they are used in treatment of some types of cancer.
CONCLUSION
While preparing my project, I learned;

Main properties of electromagnetic waves,

The most significant differences between different types of EM waves,

The main harms of highly-penetrating rays on living organisms,

The most common applications of different types of EM waves,

Some methods that are used to protect living organisms from harmful EM radiation
such as thick layers of lead.
References
For Information:

Tsokos, K. A. (2011). Physics for IB Diploma. (Fifth Edition) London: Cambridge
University Press.

WEB 1.
http://200.105.152.242/olimpiada/file.php/1/LIBROS_OLIMPIADAS/FISICA%20SE
RWAY/34-ElectromagneticWaves.pdf

WEB 2. http://physics.bu.edu/~duffy/py106/EMWaves.html

WEB 3. http://www.newworldencyclopedia.org/entry/electromagnetic_spectrum
For photos:

WEB 4. http://www.hannahjonesworks.com/radiowaves.html

WEB 5. http://www.kollewin.com/blog/electromagnetic-spectrum/

WEB 6. http://www.astrographics.com/GalleryPrintsIndex/GP4294.html

WEB 7.

http://www.tutorvista.com/content/physics/physics-iv/optics/light-dispersion.php

WEB 8. http://australianmuseum.net.au/image/X-ray-of-ancient-Egyptian-mummyskull

WEB 9. http://medchrome.com/patient/cancer-patient/the-link-between-uv-radiationand-skin-cancer/

WEB 10. http://www.universetoday.com/19244/extracting-water-from-the-moonwith-basic-home-appliances/