electromagnetic waves (chapter 11)

Question 1

what are the 5 types of electromagnetic waves?

Answer 1

radio, microwave, infrared, visible, ultraviolet, X-ray, gamma

Question 2

what are some characteristics of electromagnetic waves?

Answer 2

1.All electromagnetic waves are transverse waves
2.electromagnetic waves are made of oscillating electric and magnetic fields. They do not carry electric charges.
3. They travel without a medium at 3x10^8 m/s in a vacuum.
4. when electromagnetic waves travels from a vacuum to other media, the speed and wavelength decreases, frequency stays the same.
5. undergoes reflections and refractions
6. transfer energy
7. ionising waves (Gamma rays, X-rays) have higher frequencies and energy. They can eject electrons from atoms and molecules to create ions, causing harm by disrupting cell function and kills cells.
8. higher temperature bodies emit more and higher frequency electromagnetic waves as all material bodies emit a range of electromagnetic waves.

Question 3

what are the uses of radio waves

Answer 3

1. radio astronomy
2. Radio Frequency Identification (RFID)
3. radio and television communication
4. communication

Question 4

what are the uses of microwaves?

Answer 4

1. mobile phones
2. cooking
3. radar
4. GPS
5. cancer treatment

Question 5

what are the uses of infrared waves?

Answer 5

1. thermal imaging
2. cooking / keep warm
3. data transfer
4. remote controls
5. camera auto-focusing
6. infrared thermometer
7. intruder alarm

Question 6

what are the uses of visible light?

Answer 6

1. photography
2. telecommunication and medicine
3. artificial light for plant growth
4. hardening or curing materials

Question 7

what are the uses of ultraviolet?

Answer 7

1. disinfection and sterilisation
2. vitamin D production
3. Anti-forgery features

Question 8

what are the uses of X-rays?

Answer 8

1. X-ray imaging
2. computed tomography (CT scan)
3. security scanning
4. quality control in manufacturing

Question 9

what are the uses of gamma ray?

Answer 9

1. disinfection and sterilisation
2. quality control in manufacturing
3. radiotherapy

Question 10

what is the harmful effects of over exposure to electromagnetic radiation? (Heating)

Answer 10

sunburn
- caused by too much ultraviolet radiation
- frequent sunburns causes premature skin aging and higher risk of skin cancer

Question 11

what are the harmful effects of over exposure to electromagnetic radiation? (effects on ionising radiation)

Answer 11

ionising radiation has:
- high frequency electromagnetic waves or high energy particles
- high energy electromagnetic waves can penetrate over body easily
- knocks electron out from atoms and molecules to create harmful ions and are able to penetrate into our body more easily than high-energy particles
-when high frequency electromagnetic waves interacts with atom or molecule, it knocks an electron out from it forming a charger ion.
-charged ion might interfere with certain chemical reactions, in turn affecting particular cell process which may lead to death.