Chapter 8 - Electromagnetic Waves

Question 1

What is the order of the EM spectrum (In decreasing wavelengths and increasing frequencies)

Answer 1

Radio waves -> Microwaves -> Infrared radiation -> Visible light -> Ultraviolet radiation -> X-Rays and gamma radiation

Question 2

What is the range in wavelengths of the EM spectrum?

Answer 2

10^-15 –> 10^4

Question 3

What colours does white light contain?

Answer 3

All colours of the visible spectrum

Question 4

Name a use for infrared radiation

Answer 4

Carrying signals from remotes and optical fibres

Question 5

Name a use for microwaves

Answer 5

Carry satellite TV programs and mobile phone calls

Question 6

Name a use for radio waves

Answer 6

Radio and TV broadcasting, radio communications and mobile phone calls

Question 7

How can microwaves be harmful to humans?

Answer 7

By heating internal parts of the body

Question 8

How can infrared radiation be harmful to humans?

Answer 8

Can cause skin burns

Question 9

How does the wavelength and frequency of radio waves impact them?

Answer 9

How far they can travel, spread or how much information they can carry

Question 10

Are mobile phones save to use?

Answer 10

We don’t know

Question 11

What are optical fibres used for?

Answer 11

To transmit signals by light or infrared radiation

Question 12

Why would someone choose to transmit a signal by optical fibre instead of radiowaves or microwaves?

Answer 12

• OF can carry more information

- OF are more secure -> signals stay in fibre

Question 13

Is the wavelength of ultraviolet waves longer or shorter than visible light?

Answer 13

Shorter

Question 14

How can ultraviolet waves harm us?

Answer 14

Harms eyes and can cause blindness and is harmful to the skin

Question 15

Name a use of X-rays

Answer 15

Forming X-ray images in a hospital

Question 16

Name a use for gamma rays

Answer 16

Sterilise medical equipment, kill harmful bacteria in food, kill cancer cells

Question 17

Describe how ionisation impacts an object

Answer 17

By passing through an object and knocking off electrons -> atoms become charged

Question 18

What are charged atoms called?

Answer 18

Ions

Question 19

Name one way how x-rays are used in hospitals

Answer 19

• To make images and CT scans

- Destroy tumours near the surface of skin

Question 20

Do bones or soft tissue absorb more of an X-Ray?

Answer 20

Bones

Question 21

What can CT scans distinguish between?

Answer 21

• Different types of soft tissue

- Bone and soft tissue