1What type of waves are EM waves
Transverse
2What are the 7 components of EM waves in order of lowest to highest frequency
Radiowaves, Microwaves, Infra-red, visible light, ultraviolet, x-rays and gamma rays
3What are some other properties of EM waves
Consist of magnetic fields and electric fields oscilating 90° to each other, transfer energy from 1 place to another, carry no electric charge and obey laws of reflection and refraction
4Can EM waves travel through vacuum and if yes what is their speed
Yes with speed at $3.0\times 10^8m/s$
5What is the wave speed formula
$Frequency\times wavelength$
6If microwaves signal is at 15GHz, how does the wavelength formula look like
$\frac{3.0\times10^8}{15\times10^9}$
7What is the wavelength of radio waves, microwaves, infrared rays & visible light
$10^{3}, 10^{-2}, 10^{-5}, 10^{-6}$
8What is the wavelength of ultraviolet, x-ray and gamma rays
$10^{-8}, 10^{-10}, 10^{-12}$
9What is the relationship between frequency and wavelength of EM waves?
As the frequency increases, wavelength decreases
10What are the applications of radiowaves
AM and FM broadcasting, remote control toys,
11What are the applications of microwaves
microwave oven, 5G smartphones
12How do microwaves heat up food
They penetrate food and cause water molecules to vibrate vigorously, generating heat to cook food
13What are applications of infrared radiation
infrared thermal & motion scanners, ear thermometers
14What are applications of visible light
Used to transmit information in optical fibres for use in telecommunication. Another use is edoscopy
15What are the applications of ultraviolet radiation
Forgery detection, water purification
16What are the applications of X-rays
Airport security in X-ray machines to help check luggages at customs checkpoint. Radiography (medical imaging) to scan for bone fractures
17What are the applications of gamma rays
Treatment of cancers - kills cancer cells in gamma knife radio surgery.
18What is ionisation?
The process in which an atom or molecule loses an electron to form an ion
19What are ionising radiations
X-rays and gamma rays have high energy and hence high penetrating power. They have the capacity to cause changes in the structure of an atom of molecule by ionisation
20What do ionising radiations cause
Damage to atoms/molcules altering structure of DNA, cancers (blood)
21What are the harmful effects of overexposure to ultraviolet rays
damage to skin, aging sunburn
22What are the harmful effects of overexposure to visible light (blue light)
Macular degeneration, digital eye strain
23What are the harmful effects of overexposure to infrared rays
Radiant heat can cause pain to the skin, damage to the retina or cornea