5. LEARNING COMPETENCIES
•Cite examples of practical
applications of the different regions
of Electromagnetic (EM) waves.
•Explain the effects of EM radiation on
living things and the environment.
7. Recall
1. I have greater frequency
and energy than microwave,
but of longer wavelength
than visible light. Who am I?
Infrared
8. Recall
2. I have the greatest energy
and frequency among other
EM waves, but of shortest
wavelength.
Who am I?
Gamma Rays
9. Recall
3. I have different regions
of colors, arrange in
increasing frequency and
energy. Who am I?
Visible Light
10. Recall
4. I have the longest
wavelength and least
frequency and energy
among other EM waves
Who am I?
Radio wave
11. Recall
5. I have the longer
wavelength than x-ray
but of greater energy
than visible light ?
Ultraviolet rays/
UV rays
12. ESSENTIAL QUESTIONS
•How do regions of Electromagnetic
spectrum affects our daily living and the
environment?
•Why do gamma rays considered as the
most harmful type of electromagnetic
wave?
•How important are the radio waves in the
telecommunication and information
dissemination?
13. RADIO WAVE
•Do you wonder how we can watch our favorite
noon time show, or news program in
television? Or how we can tune in our favorite
FM radio station?
• Since in EM wave it has the longest
wavelength but of least frequency and energy
at same time, this region can be use to
transmit signals for communication and
broadcasting.
15. MICROWAVE
•Do you wonder how we can watch our favorite
NBA team in playoff, or an international event
via satellite? This is due to..
• Since this wave have greater frequency and
energy than radio wave, this EM spectrum is
used in satellite communication. How does it
happen
19. INFRARED
1. Infrared photographs taken from a satellite with
special films provide useful details of the vegetation
on the Earth’s surface.
20. USES OF INFRARED
2. Infrared scanners are used to show the temperature variation of the
body. This can be use in medical diagnosis. Also used in thermal
scanning in the airport to detect passenger’s temperature
21. USES OF INFRARED
3. Infrared remote controls are used in TVs, video-cassette
recorders and other electronic appliances.
23. USES OF INFRARED
5. Autofocus camera has a transmitter that sends out infrared
pulses.
24. USES OF INFRARED
6 Augmentative communication devices.
7. Car locking system
8. Computer’s mouse, keyboards and printers
9. Emergency response system
10. Headphones
11. Home security system
12. Navigation system
13. Signages
14. Telephones and some toys
25. VISIBLE LIGHT
The visible light shares the thinnest slice
in the electromagnetic spectrum. It lies in
between the infrared and the ultraviolet
rays. It is the only EM wave perceived by
the human eye. White light is made up of
variety of colors arranged as follows: red,
orange, yellow, green, blue, indigo,
violet. Though the colors travel at the
same speed, they come in different
wavelengths.
26. VISIBLE LIGHT
From red to violet, the colors
comes from decreasing
wavelength. Red has the
longest wavelength and violet
has the shortest. Our eyes is
sensitive to EM with a
wavelength range between
4 X 10-7 meters to 7 X 10-7
meters.
29. ULTRAVIOLET RAYS
Ultraviolet radiation lies beyond the
violet of the visible spectrum. It’s
wavelength is shorter than the visible
light but carry more energy and
higher frequency. The sun is our main
source of ultraviolet radiation, but
there are also artificial sources of UV
light.
30. USES OF UV RAYS
UV radiation in UV lamps are used by banks to
check the signature on a passbook and also used to
identify fake banknotes
31. USES OF UV RAYS
2. Ultraviolet radiation is also used in sterilizing
water from drinking fountains.
32. USES OF UV RAYS
3. Some washing powder also contains fluorescent
chemicals which glow in sunlight making shirts whiter than
white in daylight.
4. UV radiation in sunlight produced vitamin D in the skin
and gives us tanning effect.
33. X-RAYS
X-rays just comes next after ultraviolet
rays. They are shorter wavelength but
carries higher energy than the UV rays. X-
rays are produced using an X-ray tube.
They are emitted when fast moving
electrons hit a metal target. X-rays were
discovered by Wilhelm Conrad Roentgen
in 1895
34. X-RAYS
Long wavelength x-rays can penetrate the flesh
but not the bones. They are used in X-ray
photography to help doctors look inside the
body. They are useful in diagnosing bone
fracture and tumors.
35. X-RAYS
2. Short wavelength X-rays can penetrate even
through metals. They are used in industry to
inspect welded joints for faults especially in
engineering.
3. All x-rays are dangerous because they can
damage healthy living cells of the body. This is
why frequent exposure should be avoided. Too
much exposure to X-rays can damage body
tissues and can cause cancer.
36. GAMMA RAYS
Gamma rays lies at the end of the electromagnetic spectrum. They
are the shortest in wavelength and highest in frequency. They carry
the highest amount of energy; thus, they are the most dangerous.
Gamma rays are emitted by stars and some radioactive substances.
They can only be blocked with lead and thick concrete.
37. GAMMA RAYS
Gamma rays are very strong that they can kill living cells. Gamma
rays are used to treat cancer cells through the process called
radiotherapy. They are also used in sterilizing medical tools.
38. EXERCISES
Direction: Identify the type of electromagnetic wave used in each application
1. Sterilization of medical tools –
Gamma rays
2. Use to treat cancer cells –
Gamma rays
3. Remote control –
Infrared
4. Thermal scanning –
Infrared
5. Artificial lighting –
Visible light
39. EXERCISES
Direction: Identify the type of electromagnetic wave used in each application
6. RADAR –
Microwave
7. – diagnosis of bone fracture & tumors
X-rays
8. Optical fibers –
Visible light
9. Broadcasting communication –
Radio wave
10. Detecting fake banknotes –
UV rays
