Waves

Question 1

What is a wave?

Answer 1

A mechanism of transferring energy but not matter

Question 2

What is a transverse wave?

Answer 2

A wave with oscillations perpendicular to direction of energy transfer

Question 3

What is a longitudinal wave?

Answer 3

A wave with oscillations parallel to direction of energy transfer

Question 4

What is an oscillation?

Answer 4

Repetitive movement on a back-and-forth motion on both sides of an equilibrium point

Question 5

What are examples of lontigudinal waves?

Answer 5

• sound wave
• earthquake p-wave
• tsunami

Question 6

What are examples of transverse waves?

Answer 6

• light
• water
• earthquake s-wave

Question 7

What are the features of a wave?

Answer 7

• wavelength
• amplitude
• period
• frequency

Question 8

What is a wavelength?

Answer 8

The length of one wave from identical point to identical point

(in metres)

Question 9

What is an amplitude?

Answer 9

The furthest point from equilibrium point after an oscillation

This means from midline to crest/trough

Question 10

What is a period?

Answer 10

The time for one wave to pass a point from identical point to identical point

(in seconds)

Question 11

What is a frequency?

Answer 11

The number of waves passing a point every second

(in hertz)

Question 12

How do you find out a frequency?

Answer 12

frequency = 1 / Time period

Also can be number of repetitions / time taken

Question 13

How do you find out the time period?

Answer 13

time period = 1 / frequency

Question 14

What is wavespeed?

Answer 14

How many metres covered by a wave in one second

(in m/s)

Question 15

What is the electromagnetic spectrum?

Answer 15

Types of waves that can travel through a vaccum and at a speed of 3 x 10^8 m/s

Question 16

List the electromagnetic spectrum

Answer 16

radio, micro, ir, visible, uv, x-ray, gamma

Question 17

What wave properties are at the start of the EM spectrum?

Answer 17

• Low frequency
• Long wavelength

Question 18

What wave properties are at the end of the EM spectrum?

Answer 18

• High frequency
• Short wavelength

Question 19

What are radiowaves used for?

Answer 19

• TV signal
• Radio station
• Radio telescope

Question 20

What are the hazards of radiowaves?

Answer 20

There are none known

Question 21

What are the uses of microwaves?

Answer 21

• Microwave oven (heating food)
• Mobile phone satellites
• WiFi
• GPS

Question 22

What are the hazards of microwaves?

Answer 22

Internal heating of bodily tissue

Question 23

How does a microwave oven work?

Answer 23

Microwaves match natural frequency of water molecules which make them vibrate and gain thermal energy

Question 24

What are the uses of infra-red waves?

Answer 24

• Radiators
• Conventional oven
• Heat cameras
• Short range communication (TV remote)

Question 25

What are the hazards of infra-red waves?

Answer 25

Burns

Question 26

What are the uses of visible light?

Answer 26

* Photography * Optic fibres * Decoration

Question 27

What are the hazards of visible light?

Answer 27

Temporary retina damage

Question 28

What are the uses of ultraviolet light?

Answer 28

* Flourescence * Killing bacteria * Curing nail varnish

Question 29

What are the hazards of ultraviolet light?

Answer 29

* Sunburn * Skin cancer * Permanent/temporary blindness

Question 30

Why can ultraviolet light only cause skin cancer?

Answer 30

It is not energetic enough to penetrate further than the skin

Question 31

What are the uses of x-rays?

Answer 31

* X-rays or CT scans * Checking pipes for cracks

Question 32

What are the hazards of x-rays?

Answer 32

Mutation of cells

Question 33

What are the uses of gamma rays?

Answer 33

* Radiotherapy * Sterilisation of surgical instruments

Question 34

What are the hazards of gamma rays?

Answer 34

Mutation of cells

Question 35

How does radiotherapy work?

Answer 35

A concentrated beam of gamma rays are aimed at cancerous tissue from all sides and are killed from radiation exposure

Question 36

What is the Doppler Effect?

Answer 36

The change in frequency/wavelength in waves due to the relative movement of a wave source + observer

Question 37

How does the Doppler Effect work?

Answer 37

Waves emitted by an object travelling towards an observer get compressed, prompting a higher frequency