Chapter 3: Waves (Pt.3)

Question 1

What is the electromagnetic spectrum?

Answer 1

A continuous range of wavelengths.

Question 2

What type of waves are electromagnetic waves?

Answer 2

transverse waves

Question 3

What wave has the longest wavelength?

Answer 3

Radio waves. They also have the lowest frequency and lowest energy

Question 4

What wave has the shortest wavelength?

Answer 4

Gamma rays. They also have the highest frequency and highest energy.

Question 5

What are radio waves used in?

Answer 5

1. fixed and mobile radio communication
2. broadcasting
3. radar and other navigation systems
4. communications satellites
5. computer networks

Question 6

What range of frequencies do radio waves have?

Answer 6

300 GHz - 3kHz

Question 7

What are microwaves used in?

Answer 7

1. networks
2. radar
3. satellite and spacecraft communication
4. medical diathermy and cancer point-to-point communication links
5. wireless networks
6. radio astronomy
7. particle accelerators
8. spectroscopy
9. industrial heating
10. collision avoidance systems
11. garage door openers
12. keyless entry systems
13. cooking food in microwave ovens

Question 8

What range of frequencies do microwaves have?

Answer 8

300MHz - 300GHz

Question 9

List the uses of infrared radiation.

Answer 9

1. Night-vision devices
2. Infrared astronomy
3. Medical, industrial and scientific applications

Question 10

What does prolonged exposure to infrared result in?

Answer 10

Skin burns

Question 11

What does UV light cause?

Answer 11

1. Causes sun tan
2. Produces vitamins in the skin

but they can also penetrate deeper, causing skin cancer.

Dark skin can absorb more UV, reducing the amount reaching deeper tissues.

Question 12

How do you prevent exposure to UV?

Answer 12

wearing protective clothing like a hat.
Using sunscreen lotion

Question 13

List some applications of UV light.

Answer 13

1. sterilising water.
2. fluorescent paints and clothes washed in some detergents to fluoresce.

Question 14

Are X-rays harmful?

Answer 14

Yes, they carry enough energy to ionize atoms and disrupt molecular bonds.
In medical imaging, this increased cancer risk is generally greatly outweighed by the benefits of examination

Question 15

Why are X-rays used to image the inside of opaque objects?

Answer 15

Hard X-rays can traverse relatively thick objects without being much absorbed or scattered.

Question 16

What can gamma rays result in?

Answer 16

They are penetrating and can cause mutations in cells leading to cancer.

Question 17

How do you protect yourself from gamma rays?

Answer 17

By wearing radiation badges to measure amount of radiation exposure in their body

Question 18

List the benefits of a digital signal.

Answer 18