Waves

Question 1

What are longitudinal waves

Answer 1

Are oscillations that move left to right, parallel to the direction of energy transfer. They show areas of compressions ad rarefactions

Question 2

What are transverse waves

Answer 2

Transverse waves are oscillations that move up and down, perpendicular to the direction of energy transfer.

Question 3

Examples of longitudinal waves

Answer 3

• sound waves
• seismic p waves
• ultrasound waves

Question 4

Examples of transverse waves

Answer 4

• water ripples
• all of the waves on the electromagnetic spectrum
• seismic S waves

Question 5

What are electromagnetic waves

Answer 5

They are waves which transfer radiation from the source of the waves to the absorber.

they can travel through a vacuum, and travel through space at the same speed that they travel through the air

Question 6

The electromagnetic spectrum

Answer 6

Lowest frequency = radio waves
- microwaves
- infrared waves
- visible light
- Ultraviolet waves
- X rays
Highest frequency = Gamma rays

Question 7

What type of waves are electromagnetic waves

Answer 7

They are transverse

Question 8

Formula for wave speed

Answer 8

Wave speed = frequency x wavelength

Question 10

Speed is equal to

Answer 10

Speed = frequency x wavelength

Question 11

What is the defection of wavelength

Answer 11

The distance from one point on one wave to the same point on another wave.

Question 12

What is frequency

Answer 12

The number of complete waves that pass thought a given point in one second

Question 13

Amplitude

Answer 13

Half the distance from peak to trough

Question 14

Wave speed

Answer 14

How quickly the wave travels from its source

Question 15

Uses of radio waves

Answer 15

Communications, in phones, in radios

Question 16

Uses of microwaves

Answer 16

In phones, for communication

Question 17

Uses for infared waves

Answer 17

Used in remote controls, and electrical heaters, toasters

Question 18

What are ultraviolet waves used for

Answer 18

Killing bacteria, suntanning

Question 19

Uses of radio waves in medicine

Answer 19

Images inside body

MRI

Question 20

Gamma waves

Answer 20

Disinfection and sterilisation

Question 21

What happens to sound waves in water

Answer 21

In water, sound waves have the same frequency, increased speed and increased wavelength

Question 22

If the frequency increases

Answer 22

The speed stays the same and the wavelength decreases

Question 23

What type of waves are light

Answer 23

Transverse

Question 24

Describe a difference between ultrasound waves and ripples on the surface of water.

Answer 24

Ultrasound waves are longitudinal
Water ripples are transverse

Question 25

The ultrasound scanner is made from a solid ceramic material. As the wave enters the body, the speed ………….

Answer 25

Decreases

Question 26

Explain how ultrasound waves are used to measure the thickness of different organs

Answer 26

-> measure tune between reflections -> use distance = speed / time -> half the distance to find the thickness of organ

Question 27

A doctor uses ultrasound instead of x rays explain why

Answer 27

X rays are ionising

Question 28

In a scan using ultrasound pulses, three layers of tissue are detected, with each layer having a different thickness. Describe and explain how the results from the detector can show t - there are three layers - each layer has a different thickness

Answer 28

-> 3 relefctions are returned from each pulse sent -> each pulse takes different times to travel there and back -> can conclude there are three pulses as the larger the thickness of the layer, the longer it takes for the pulse to be reflected

Question 29

The teacher increases the frequency of the water waves. Describe what happens to the speed and the wavelength of the water waves.

Answer 29

Speed stays the same Wavelength reduces

Question 30

A model water waves using a slinky shows that the wave travels not the water. Explain why.

Answer 30

The could of the slinky stay in the same place

Question 31

A sound wave travels in air and enters water. What happens to the sound wave as it enters the water?

Answer 31

Speed increases Frequency stays the same Wavelength increases

Question 32

Why do the speed and wavelength increase when a sound waves enter water but frequency doesn’t change

Answer 32

-> Water is denser and particles are closer — better transmission, meaning speed increases -> Stays the same, as Frequency depends on the source (doesn’t change across media) -> Speed=Frequency×Wavelength. If speed increases and frequency is constant, wavelength increases too.

Question 33

Describe how water particles move in a transverse water wave.

Answer 33

Water particles move at right angles to direction of energy transfer

Question 34

What happens to the frequency across different mediums

Answer 34

The frequency remains the same as the frequency is dependant on the source not the medium

Question 35

What happens if you remain in the same medium but you increase the wavelength

Answer 35

If your in The same medium, the speed remains constant, meaning that the frequency will go down However if you go across a different medium then frequency remains constant meaning that the speed will increase

Question 36

What halogens to the speed across different mediums

Answer 36

If the wave enters a denser medium it means the speed will increase

Question 37

What are the dangers the higher frequency cy waves

Answer 37

-> UV rays can cause cataracts or skin cancer -> excess exposure radio waves can cause cancer -> large exposure to gamma rays can also kill damage healthy cells

Question 38

How are Infared rays used in imaging

Answer 38

-> thermal imaging camera produces thermogram -> red / orange shows excess infared radiation -> hotter areas emit more radiation

Question 39

How are X-rays used for imaging

Answer 39

-> bones absorb X-rays -> X-rays pass through soft tissue, meaning photographic film behind it goes black -> since the bones absorb the X-rays the film there is white where the bones are -> the high contrast helps shows injuries or breaks in the bone

Question 40

Why are X-rays not used to detect issues with organs

Answer 40

X-rays pass through soft tissue

Question 41

How are gamma rays used for imaging

Answer 41

-> tracer us a substance with radioactive material -> tracer is injected / swallowed / inhaled -> the tracer is absorbed by the different organs -> detector picks up where there are very high / very low levels of the tracer -> can help determine where something is wrong

Question 42

What haloes to the frequency kf radiation is emitted by the hot object

Answer 42

Increases