4. Electromagnetic Waves

Question 1

Electromagnetic Waves

6 Properties

Answer 1

All electromagnetic waves:

1. are made up of electric and magnetic fields oscillating perpendicularly to the direction of wave propagation
2. are transverse waves
3. do not carry electric charges
4. can travel without a medium, with a speed of 3.0 x 10⁸ m/s in a vacuum (no matter what type)
5. undergo reflection and refraction
6. transfer energy

v = fλ applies to all electromagnetic waves

Question 2

State the order of electromagnetic waves based on increasing wavelength

Answer 2

1. Gamma rays
2. X-rays
3. Ultraviolet radiation
4. Visible Light
5. Infrared radiation
6. Microwaves
7. Radio waves

Question 3

State the order of electromagnetic waves based on increasing frequency

Answer 3

1. Radio waves
2. Microwaves
3. Infrared Radiation
4. Visible Light
5. Ultraviolet radiation
6. X-rays
7. Gamma rays

Question 4

Radio Waves

Examples

Answer 4

1. Television and radio communication
2. Radio telescopes for radio astronomy

Question 5

Microwaves

Examples and Hazardous Effects

Answer 5

Examples:
1. Microwave oven
2. Wi-fi signals
3. Mobile Phone communication
4. Global Positioning System

Hazardous effects:
Heating effect (temperature increases)

Question 6

Infared Radiation

Examples and Hazardous Effects

Answer 6

Examples:
1. Remote control
2. Intruder alarm
3. Thermal imaging (infared camera)

Hazardous effect:
Heating effect (temperature increases)

Question 7

Visible Light

Examples

Answer 7

1. Photography
2. Optical fibres in medicine and telecommunication

Question 8

Ultraviolet Radiation

Examples and Hazardous Effects

Answer 8

Examples:
1. Sterilisation of medical equipment
2. Sunbed for artificial tanning

Hazardous effects:
1. Prolonged exposure to UV radiation can lead to sunburns, premature aging and increased risk of skin cancer
2. UV radiation can be ionising

Question 9

Ionising Radiation

What is it and Effects

Answer 9

• Radiation that has the energy to remove elections from atoms or molecules, thereby ionising them.
• Exposure to ionising radiation can lead to cell death, mutations and abnormal cell division.
• May cause cancers such as leukaemia or deformities to a developing foetus

Question 10

X-rays

Examples and Hazardous Effects

Answer 10

Examples:

1. Scan luggage for prohibited items at airport
2. Radiograpy to produce X-ray imaging to diagnose fractured bones or tooth decay

Hazardous Effects:

1. Ionising radiation

Question 11

Gamma Rays

Examples and Hazardous Effects

Answer 11

Examples:
1. Sterilisation of medical equipment
2. Sterilisation of food

Hazardous Effects:
1. Ionsing radiaton