Radio waves are a type of electromagnetic radiation that have wavelengths longer than infrared light. They were discovered in 1897 by Heinrich Hertz, after whom the unit of frequency is named. Radio waves are produced by alternating current circuits attached to antennas and have frequencies ranging from 300 GHz to 3 kHz. They are used for transmitting information such as sound, television signals, and data without wires for purposes like communication, GPS, Wi-Fi, and Bluetooth. While radio waves have enabled many modern technologies, prolonged exposure to high amounts may cause health issues like cancer, so it is best to limit direct exposure when possible.

1. RADIO WAVES

2. Some terms
•Electromagnetic radiation is a form of energy that is all around us and
takes many forms, such as radio waves, microwaves, X-rays and
gamma rays.
•The EM spectrum is divided into bands: Radio Waves, Microwave,
Infrared, Visible, Ultraviolet, X-Rays, and Gamma Rays

3. The visible light we see is only a small fraction of
the total EM spectrum
Radio waves can be as short as 1 mm or many
kilometers long!
The
Electromagnetic
Spectrum

4. Radio Waves (What are radio
waves?)
 Radio waves are part of a larger group of
waves classified all together
as electromagnetic radiation. This large
group of waves is broken down into smaller
groups based upon their frequencies and
wavelengths.
 They are a type of electromagnetic
radiation with wavelengths in the
electromagnetic spectrum longer
than infrared light. In fact, they are the

5. Radio Waves
 Radio waves were discovered by Heinrich Hertz in
1897. The SI unit of frequency was named after him.
 They are produced by alternating current (AC) circuit
attached to an antenna.
FACT:
Radio waves have
frequencies as high as
300 GHz to as low as 3 kHz
The sun and the planet Jupiter
are extraterrestrial sources of
radio waves.

6. USES
The prime purpose of radio is
to convey information from
one place to another through
the intervening media without
wires.
Besides being used for
transmitting sound
and television signals, radio
waves is used for the
transmission of data in coded
form
used also for sending out signals
and picking up their reflections
from objects in their path.
also enables astronauts to
communicate with the earth
from the moon and carry
information from space
probes as they travel to
distant planets

7. USES
Automatic doors, Wi-FI,
and Bluetooth make use of
radio waves
GPS and radio frequency
identification also makes
use of radio waves.

8. Phones convert your voice into
an electrical signal, which is then
transmitted as radio waves and
converted back into sound by
your friend’s phone. A basic
mobile phone is therefore little
more than a combined radio
transmitter and a radio receiver,
quite similar to a walkie-talkie or
CB radio.
RADIO WAVES IN CELLULAR
PHONES

9. RADIO WAVES IN CELLULAR PHONES
In order to remain portable,
mobile phones need to have
relatively compact antennas
and use a small amount of
power. This means that
mobile phones can send a
signal over only a very short
range, just like a walkie-
talkie.
(Antenna of iPhone 5S)

10. HARMFUL EFFECTS OF RADIO WAVES
 Cell phone RFs may instigate brain
tumors and even cancer.
 Exposures to RFs have been
unofficially linked to sleep
disorders, headaches, and other
neurological problems.
 Claims that cell phones promote
“radio wave sickness” have
propagated through society for
years. Associated illnesses include
multiple sclerosis, depression,
autism, and a slew of other common
ailments.
 Continued exposure to large
amounts of radio waves can cause
health disorders like leukemia and
cancer.
 Thermal effects caused by radio
waves on the human body are
especially dangerous, as radio waves
can quickly heat tissues to lethal
levels.

11. HOW DO YOU PREVENT THESE HARFUL EFFECTS?
 Eating healthy, exercising, and
taking extra supplements, your
immune system will be
strengthened. This will minimize the
damaging effects of EMR
(electromagnetic radiation) and cell
phone radiation exposure. Healthy
eating and drinking lots of water will
also allow for quicker repair of
damage already
done.
 Reduce or stop using other wireless
devices
 Keep laptops away from the body
and don’t use a laptop while it rests
on the lap. Sit back from computer
monitors and screens as much as
possible.
 Use your cell phone only where
reception is good
 Keep your cell phone away from
your body when it’s on: The most
dangerous place to be is within
about six inches of the emitting
antenna.

12. HOW DO YOU PREVENT THESE HARFUL EFFECTS?
 Keep all electronic devices like
alarm clocks, radios and cordless
phones at least six feet away from
your head during sleep. In our
house, we unplug everything in our
bedroom every night when we go to
sleep. And we don't just put our
computers to "sleep", we shut them
down completely.
 Use safer headset technology: Wired
headsets will certainly allow you to
keep the cell phone farther away
from your body. However, if a
wired headset is not well-shielded
(and most of them are not) the wire
itself acts as an antenna,
transmitting radiation directly to
your brain. Make sure that the wire
used to transmit the signal to your
ear is shielded.

13. Quiz
Please get 1/4 sheet of paper

14. 1. It is a form of energy that is all around us and takes
many forms, such as radio waves, microwaves, X-rays
and gamma rays.
2. The longest of all electromagnetic waves
3-4. Give at least two uses of the answer in number 2.
5. He discovered the answer in number 2.
6-8. Give at least three harmful effects.
9-10. The Extraterrestrial sources of radio waves.

15. THANK YOU :)