All about the electromagnetic waves than you can learn in Grade 10

1. Quarter 2 – Module 1:
Different Forms of
EM Waves

2. You are surrounded with thousands of
waves which collide with your body
and some pass through you. Most of
these waves are invisible but some can
be perceived.

3. The warmth of the sun and the light
that you see are just few of them.
These waves share similar
characteristics, yet, they are unique in
some ways. These waves are called
electromagnetic (EM) waves.

4. In your previous lessons, you have
learned about mechanical waves -
those that require medium to transfer
energy. EM waves are different from
mechanical waves in some important
ways.

5. EM waves are disturbance that
transfer energy through a field. They
can also travel through a medium but
what makes them strange is that they
can transmit through empty space.

6. Radiation is the term used to describe the
transfer of energy in the form of EM wave.
For a mechanical wave to travel, it must
vibrate the medium as it moves. This
makes use of some of wave’s energy. In
the end, it makes them transfer all energy
to the medium.

7. As for EM wave, it can travel to empty
space or vacuum so it does not lose its
energy. This enables it to cross great
distance such as that from the sun to the
Earth (which is almost a vacuum) without
losing energy.

8. EM waves can also transmit with a
material medium. They can also transfer
energy to the medium itself. When they
interact with matter, their energy can be
converted into many different forms. With
these characteristics, EM waves are used
for a wide variety of purpose.

9. Electromagnetic radiation is all around us.
Some are unnoticeable, yet a lot of our
activities make use of these
electromagnetic waves from texting to
cooking. But what are electromagnetic
waves?

11. What’s New
Let’s try and make
some waves!

12. Why does each created
wave look differently?​
Answer:
The amount of force applied contributes to
the appearance or size of waves.

13. Waves move through some sort of medium. If you
flick the end of a jumping rope or string, a wave
moves along the rope or string. A wave is generally
considered to be a regular series of alternating
upward and downward pulses propagating down
the rope. Modeling the propagation of a pulse is
thus equivalent to modeling the propagation of a
wave.

14. This is the reason why when we move the
rope faster it creates smaller waves or
loops but at faster rates. It only means that
the smaller waves we create, the higher
number we can get.

15. On the other hand, creating waves using slow
movements will give us larger waves but in a
smaller number. This is because the ropes
travel farther compared to the smaller waves.
The aptitude is also higher which greatly
contributes to the number of waves created.

16. What Is It

17. When you move your hands up and
down while holding one end of the
rope, you create wave on the rope.
The waves you created may look
different depending on how fast you
move your hand.

18. Similarly, if you move an electrically
charged object back and forth in an
empty space, you’ll create
electromagnetic waves in space. But
what is an electromagnetic wave?

19. Electromagnetic wave (EM
wave) or electromagnetic
radiation is a wave that is
created as a result of vibrations
between an electric field and
magnetic field, hence known as
‘electromagnetic wave’.

20. Recall Oersted’s discovery: A
changing electric field produces
magnetic field. A changing magnetic
field is therefore produced around a
vibrating charge. And according to
Michael Faraday, the changing
magnetic field will produce electric
field.
Hans Christian Oersted

21. A wave carries energy as it
propagates, EM wave does the same,
too. EM waves can travel through
anything even on vacuum (empty
space), meaning they do not need any
medium to travel. They travel in a
vacuum at a speed of 3x10^8 m/s.

22. What’s More

23. There are seven different types of EM
waves. They are arranged in a gradual
progression from the waves of lowest
frequency to highest frequency. This
arrangement of EM waves is called
electromagnetic spectrum.

24. In order of increasing frequency,
the EM spectrum includes radio
waves, microwaves, infrared,
visible light, ultraviolet, X-ray,
and gamma ray.

25. Now let’s strengthen your concepts
regarding the different EM waves by
comparing their relative wavelengths and
frequencies. And as you move along,
discover some characteristics of EM waves.
So if you’re ready to ride the waves,
answer the following enrichment activities
and dive into the world of EM waves.

26. Enrichment activity 1:
Determining the
Wavelength Ranges of
Each Form of EM Wave

27. Wavelength is the distance
between crest to crest or trough to
trough. EM waves are bounded at
different ranges. Meaning each
type of EM waves has upper and
lower limits on the spectrum.

28. Using Figure 1, determine the
wavelength ranges of each of the
forms of electromagnetic waves. On a
separate sheet of paper, copy and
answer the given table on page 13.
Afterwards answer the questions that
follow.

29. Figure 1. Wavelength Ranges of EM Waves

31. Q1. Which electromagnetic wave has
the longest wavelength?
Answer: RADIO WAVE

32. Q2. Which electromagnetic wave has
the shortest wavelength?
Answer: GAMMA RAY

33. Q3. Observe what happens to the wavelength of the
electromagnetic waves as they progress (goes
rightward from the figure). Does the wavelength of
the EM waves increase or decrease as we go from
radio wave to gamma ray?
Answer: The wavelength of EM
waves decreases

34. Enrichment Activity 2:
Determining the
Frequency Ranges of
Each Form of EM Wave

35. What Is Wave Frequency?
The number of waves that pass a fixed
point in a given amount of time is wave
frequency. Wave frequency can be
measured by counting the number of
crests (high points) of waves that pass the
fixed point in 1 second or some other time
period.

36. What Is Wave Frequency?
The higher the number is, the greater the
frequency of the waves. The SI unit for
wave frequency is the hertz (Hz), where 1
hertz equals 1 wave passing a fixed point in
1 second. The figures on the next slide
show high-frequency and low-frequency
transverse waves.

37. What High and Low Wave
Frequencies Look Like

38. When determining the wavelength
and frequency ranges of each type
of EM waves, you start from its
lower limit to its upper limit on the
spectrum.

39. Figure 1. Wavelength Ranges of EM Waves

40. Next up, let us compare the
frequencies of different EM waves.
Copy and answer the table on
page 16, refer to Figure 2, then
answer the questions that follow.
Use a separate sheet of paper for
your answer.

41. Figure 2. Frequency Ranges of EM Waves

43. Q1. Which among the EM waves has
the highest frequency?
Answer: GAMMA RAY

44. Q2. Which among the EM waves has
the lowest frequency?
Answer: RADIO WAVE

45. Q3. The energy of an EM wave also
depends on its frequency, which means
waves with higher frequency has
higher energy too. Which among the
EM waves has the highest energy?
Answer: GAMMA RAY

46. Q4. Which among the EM waves has
the lowest energy?
Answer: RADIO WAVE

47. Q5. What happens to the frequency of
the electromagnetic waves as it
progresses? Does the frequency of the
EM waves increase or decrease as we
go from radio wave to gamma ray?
Answer:
The EM wave increases

48. End of Quarter 2 - Module 1