Page 227 - text book form physics kssm 2020

Chapter 5
Waves
File

Electromagnetic waves: • For electromagnetic waves,
• are transverse waves the formula
• do not need medium for propagation v = f λ is rewritten as c = f λ.
• can propagate through vacuum • Continuous spectrum means
• have speed in vacuum, c = 3.00 × 10 m s , and move with no specifi c boundary which
8
–1
lower speed in any medium. separates two adjacent
• show phenomena of refl ection, refraction, diff raction and types of waves.
interference under suitable conditions

Electromagnetic Spectrum
Seven types of electromagnetic waves form a continuous spectrum known as electromagnetic
spectrum. Figure 5.70 shows the electromagnetic spectrum.

Increasing wavelength

10 –11 10 –10 10 –9 10 –8 10 –7 10 –6 10 –5 10 –4 10 –3 10 –2 10 –1 1 10 1 10 2 10 3 10 4 Wavelength (m)

Gamma X-ray Ultraviolet Infrared Microwave Radio wave
ray ray ray

10 20 10 19 10 18 10 17 10 16 10 15 10 14 10 13 10 12 10 11 10 10 10 9 10 8 10 7 10 6 10 5 10 4 Frequency (Hz)

Increasing frequency
Visible light

Wavelength 400 500 600 700 750 nm

Figure 5.70 Electromagnetic spectrum
Th e energy carried by electromagnetic waves is directly proportional
to its frequency. Th is means gamma ray and X-ray carry large
amount of energy. Th ese waves need to be handled properly as not
to endanger the users. Smartphone as a remote
control device
Applications of Electromagnetic Waves Surf the Internet to get
guidelines on how to confi gure
Electromagnetic spectrum is made up of seven types of smartphones to function as
electromagnetic waves and covers a very wide range of wavelengths. television or air conditioner
As such, applications of electromagnetic waves encompass various remote control.
fi elds. With the rapid advancements in science and technology, new
applications are discovered from time to time. What applications
of electromagnetic waves do you know?

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5.7.2
5.7.1
5.7.1 5.7.2 5.7.3
5.7.3