Electromagnetic radiation consists of electrical and magnetic fields that oscillate perpendicular to each other and travel together at the speed of light. Wavelength is the distance between wave peaks, and is inversely related to frequency, which is the number of waves that pass a point per unit time. Electromagnetic waves include radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays, with decreasing wavelengths and increasing frequencies and energies in that order.

7. Electromagnetic radiation has electrical field (E) which
varies in magnitude in a direction perpendicular to the
direction in which the radiation travels, and a magnetic
field (M) oriented at right angles to the electrical field.
Both fields travel at the speed of light (c).
The Electric and Magnetic Fields of the Electromagnetic Energy

9. Wavelength and Frequency
Wavelength is the distance between one wave peak and the
other.
Wavelength is usually represented by the Greek letter lambda
The longer the wavelength the lesser the energy content and
vice versa.
Wavelength is measured in metres (m) or some factor of metres
such as nanometres, micrometres or centimetres.

10. Frequency is the number (cycle of wave) of wave peaks
that passes through a fixed point per unit time.
It is measured in hertz (Hz), which is equivalent to one
cycle per second, and various multiples of hertz.
Wavelength and frequency are related by the following
formula:

11. WHAT IS EMR????

13. Electromagnetic Waves
Transverse waves without a medium! (They
can travel through empty space)

14. Electromagnetic waves travel VERY FAST –around
300,000 kilometres per second (the
speed of light).
At this speed they
can go around the world 8 times in
one second.
f light).

15. Notice the wavelength is long (Radio waves)
and gets shorter (Gamma Rays)

16. RADIO WAVES
Have the longest wavelengths and
lowest frequencies of all the
electromagnetic waves

17. Global Positioning Systems (GPS) measure
the time it takes a radio wave to
travel from several satellites to the
receiver, determining the distance to
each satellite.

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19. A radio picks up radio waves through an
antenna and converts it to sound waves.
Each radio station in an area broadcasts at
a different frequency.
# on radio dial tells frequency.

20. MRI
(MAGNETIC RESONACE IMAGING)
Uses Short wave radio waves with a magnet to create an
image.

21. MICROWAVES
Have the shortest wavelengths and the
highest frequency of the radio waves.
Used in microwave ovens.
Waves transfer energy to the water in
the food causing them to vibrate which
in turn transfers energy in the form of
heat to the food.

22. INFRARED RAYS
Infrared= below red
Shorter wavelength and higher frequency
than microwaves.
Thermogram—a picture that shows regions of
different temperatures in the body.
Temperatures are calculated by the amount
of infrared radiation given off.

23. VISIBLE LIGHT
Shorter wavelength and higher frequency
than infrared rays.
Electromagnetic waves we can see.
Longest wavelength= red light
Shortest wavelength= violet (purple)
light

25. Visible Spectrum
The visible portion of the electromagnetic spectrum
is always considered to be a spectrum within a
spectrum.
The visible spectrum consists of the light which our
eyes can detect.
It is important to note how small a portion of the
electromagnetic spectrum is represented by the
visible region.

26. ULTRAVIOLET RAY
Shorter wavelength and higher
frequency than visible light Carry more
energy than visible light
Used to kill bacteria.
(Sterilization of equipment)

27. Too much can cause skin cancer. Use sun block to
protect against (UV rays)

28. X- RAYS
Shorter wavelength and higher frequency than
UV-rays Carry a great amount of energy
Can penetrate most matter
Bones and teeth absorb x-rays. (The light part
of an x-ray image indicates a place where the
x- ray was absorbed)

29. Use engineers to check for tiny cracks in
structures.
– The rays pass through the cracks and the
cracks appear dark on film
.

30. GAMMA RAYS
Shorter wavelength and higher
frequencythan X-rays
Carry the greatest amount of energy
and penetrate the most.
Used in radiation treatment tokill
cancer cells.
Can be very harmful
if not used correctly.

31. Exploding nuclear
weapons emit
gamma rays