16. Objectives:
a. Trace the development of the
electromagnetic wave theory
b. Describe how electromagnetic wave is
produced and propagated.
c. Compare the Electromagnetic Waves in
terms of wavelength, energy and frequency.
17. Hans Christian Oersted 1777--1851
Showed how a current
carrying wire behaves
like a magnet.
22. Electromagnetic Waves…
● Do not need matter to transfer
energy.
● Are made by vibrating electric
charges and can travel through
space by transferring energy
between vibrating electric and
magnetic fields.
23. How do moving charges create
magnetic fields?
● Any moving electric charge is surrounded by an
electric field and a magnetic field.
24. What happens when electric and
magnetic fields change?
A changing magnetic field
produces an electric field and a
changing electric field produces
a magnetic field.
25.
26. Making Electromagnetic Waves
● When an electric charge vibrates, the electric
field around it changes creating a changing
magnetic field.
28. Making Electromagnetic Waves
● An EM wave travels in all directions. The figure
only shows a wave traveling in one direction.
29. Making Electromagnetic Waves
● The electric and magnetic fields vibrate at right
angles (perpendicular to each other) to the
direction the wave travels so it is a transverse
wave.
30. Properties of EM Waves
All matter contains charged
particles that are always
moving; therefore, all objects
emit EM waves.
31. Among the examples of EM waves
are radiowaves, microwaves,
infrared, visible light, ultraviolet, x-
rays and gamma rays. All EM
waves travel at a speed of 3 X 108
m/s in a vacuum and denoted as c,
the speed of light.
32. Since all the electromagnetic waves have
the same speed, as wavelength decreases,
the frequency of the wave increases as
expressed in the equation
v=λf
where: v is the wave speed, or c (speed of
light) expressed in meter per second,
f is the frequency expressed in Hertz
λ is the wavelength expressed in meters
33. Speed
All electromagnetic waves travel at a
speed of 300,000 km/s (3 x 108m/s)
in a vacuum of space. However, when
electromagnetic waves travel through
matter, they slow down. The speed of
the wave depends upon the material
they travel through.
35. Frequency
The frequency is the number of waves
that pass a certain point in a specified
amount of time. Typically, frequency is
measured in units of cycles per second or
waves per second. One wave per second
is also called a Hertz (Hz) and in SI units is
a reciprocal second (s−1).
36. Wavelength
Wavelength is defined as the distance
measured from one crest of a wave to the
next crest or from one trough to the second
trough.
37. In an equation, wavelength is
represented by the Greek letter
lambda (λ). Depending on the type
of wave, wavelength can be
measured in meters, centimeters, or
nanometers (1 m = 109 nm). To find
wavelength ( λ ), use this equation
v=λf
38. ACTIVITY 1A: MATCH ME!
Scientists Contributions
___1.Ampere a. Contributed in developing
equations that showed
the relationship of electricity
and magnetism
____2. Faraday b. Showed experimental
evidence of electromagnetic
waves and their link to light
39. Scientists Contributions
___3. Hertz c. Demonstrated the magnetic
effect based on the
direction of current
___4. Maxwell d. Formulated the principle
behind electromagnetic
induction
___5. Oersted e. Showed how a current-
carrying wire behaves like a
magnet
40. ACTIVITY 1B. LET’S TALK ABOUT EM!
Directions: Write T if the statement is True,
F if the statement is false.
_______1. Electromagnetic waves transfer
energy through vacuum.
______ 2. A wave is a disturbance that
transfers energy.
41. ______ 3. Most EM waves are invisible and
undetectable.
______ 4. The electric field and the
magnetic field oscillate parallel to each
other
______ 5. As wavelength increases, the
frequency of wave also increases.
42. ACTIVITY 1C: FILL ME!
Direction: Complete the statements below by filling
in with correct word(s) found in the box. (1 point
each)
43. 1. A changing magnetic field produces an ________.
2. A changing electric field produces a __________.
3. The successive production of electric and magnetic
field results to the creation of
____________________wave.
4-5. The electric and magnetic fields vibrate
_______________to each other to the direction the
wave travels so it is a _________________________
wave.
44. 4-5. The electric and magnetic fields vibrate
_______________to each other to the direction the
wave travels so it is a
_________________________ wave.
6. James Clerk Maxwell formulated the
________________- which says that an oscillating
electric current should be capable of radiating
energy in the form of electromagnetic waves.
45. 7. The one who formulated the principle behind
electromagnetic induction was _____________.
8. ___________________ contributed in developing
equations showing the relationship of electricity and
magnetism.
9-10. EM waves can travel through a ____________
with a speed value of
__________________.
46. Directions: Make a Comic Strip about the scientist
contributions on the development of electromagnetic
wave theory. Refer to the rubric below for your
guidance in making your output.
Remember:
A comic strip is a sequence of drawings in boxes
that tell an amusing story, or a form of story-telling,
which uses drawings or cartoon characters to tell a
story.
