2.1 Waves

Question 1

What do waves do ?

Answer 1

Waves transfer energy through vibrations

Question 2

What are the 2 types of waves ?

Answer 2

• Transverse waves
• Longitudinal waves

Question 3

What happens in transverse waves ?

Answer 3

In transverse waves the particles travel perpendicular to the energy travel

Question 4

What happens in longitudinal waves ?

Answer 4

In longitudinal waves the particles travel parallel/ in the same direction to the energy travel

Question 5

What is the area of a longitudinal wave called when it is closer together ?

Answer 5

A compression

Question 6

What is the area that is spread further apart called on a longitudinal wave ?

Answer 6

A rarefraction

Question 7

What are examples of transverse waves ?

Answer 7

• Water waves
• Electromagnetic waves
• S waves

Question 8

What are examples of longitudinal waves ?

Answer 8

• Sound waves
• Ultrasound waves

Question 9

What is a wavelength ?

Answer 9

The wavelength is the distance between two neighboring crests of a transverse wave or the distance between two compressions on a longitudinal wave

Question 10

What is amplitude ?

Answer 10

The distance measured from the middle of the wave to the height of the crest or the depth of the trough

Question 11

What is the frequency ?

Answer 11

The number of complete waves that pass a certain point each second

Question 12

What is the amplitude of a longitudinal wave ?

Answer 12

The amplitude of a longitudinal wave is the maximum distance a particle moves from the centre of its motion

Question 13

What is the wave equation

Answer 13

V = F Y

Question 14

How are sound waves produced ?

Answer 14

Sound waves are produced when an object vibrates

Question 15

What is the frequency of sound ?

Answer 15

The frequency of sound is the number vibrations per second

Question 16

Where does the human hearing range start ?

Answer 16

20Hz

Question 17

What is considered ultrasound ?

Answer 17

Any sound above 20,000Hz

Question 18

How do ultrasounds work?

Answer 18

Ultrasound waves are partially reflected when they meet a boundary between two different media. The time taken for the reflection to reach a detector is a measurement of how far away the boundary is.

Question 19

What can ultrasonic scanners be used for ?

Answer 19

• Producing images of organs inside the body
• Producing an image of a baby inside the womb

Question 20

How does an ultrasonic scanner work ?

Answer 20

The probe produces and detects pulses of ultrasonic waves.
For each pulse it sends out it detects pulses from the different boundaries in the path the transmitted pulse

Question 21

What are the advantages of using ultrasonic waves instead of X rays for medical scanning ?

Answer 21

• X-rays can cause damage to cells
• Ultrasound can detect muscles

Question 22

What is the ultrasound used for in industry ?

Answer 22

To detect defects in metal.

Question 23

How does ultrasound detect flaws in metal castings ?

Answer 23

• A flaw such as internal crack is a boundary inside the metal
• The ultrasonic waves are partially reflected from the boundary
• An ultrasonic transmitter on the metal surface sends pulses of ultrasonic waves into the metal object
• A detector is placed on the surface next to the transmitter and detected pulses are displayed on an oscilloscope screen.

Question 24

How does an ultrasonic cleaning machine work?

Answer 24

The ultrasonic waves passed through a tank of water dislodge the dirt particles from the surfaces of the object that was placed in the water

Question 25

What is SONAR ?

Answer 25

SONAR is SOund Navigation And Ranging

Question 26

What is SONAR used for and how ?

Answer 26

- SONAR uses sound pulses to detect objects under water. - Sound waves are sent down towards the ocean floor, a detector in a boat records the time that the reflected wave takes and hence the depth to the floor can be calculated.

Question 27

How do you carry out echo calculations ?

Answer 27

Use D = S x T but use x2 the distance because of the reflections

Question 28

What is the electromagnetic spectrum ?

Answer 28

It is a spectrum made up of a group of waves. It is continuous but the wavelengths with it can be grouped into types of increasing wavelength and decreasing frequency

Question 29

What is the electromagnetic spectrum from lowest to highest frequency ?

Answer 29

- Radio waves - Microwaves - Infrared - Visible light - Ultra violet - X-ray - Gamma

Question 30

What is a mnemonic to remember the electromagnetic spectrum ?

Answer 30

Reading My Instructions is Visible Under X-ray Glasses

Question 31

What are the properties of electromagnetic waves ?

Answer 31

- They are transverse waves - They can travel in a vacuum - They transfer energy - They move at the speed of light - They move energy not particles

Question 32

What are the uses of radio waves ?

Answer 32

- Radio waves are used for communication. - Television and radio waves have wavelengths typically of 1m

Question 33

What are the uses of Microwaves and radar waves ?

Answer 33

- Reheating food - Phone service/ signal 4g/5g - satellite communication - microwaves pass readily through the Earths atmosphere

Question 34

How are microwaves used to heat up food ?

Answer 34

- Microwaves give water molecules kinetic energy which heats the food

Question 35

How can microwaves be a danger to the human body ?

Answer 35

Our bodies are majority water meaning that a microwave can raise our body temperature

Question 36

What is RADAR ?

Answer 36

RADAR is RAdio Detection and Ranging - Radar is a powerful beam microwaves, they have wavelengths from a few mm to 1m - They are used to track objects which may be a large distance away but cannot be used in water

Question 37

What is Infrared radiation and what are the uses of infrared radiation ?

Answer 37

- Infrared radiation is given out by warm objects. The hotter an object is the more infrared radiation is given out by that object. Uses include: - TV remote - Infrared goggles - Toaster or oven

Question 38

What are the dangers of infrared ?

Answer 38

- Danger to the skin as overexposure to infrared radiation causes damage to cells, such as sunburn

Question 39

What is visible light ?

Answer 39

- Visible light is given out by hot objects - Visible light is the only part of the spectrum that we can see and each colour of the spectrum has a different wavelength

Question 40

What are uses of visible light ?

Answer 40

- Seeing - Photography - Photosynthesis - Microscope

Question 41

What is ultraviolet radiation produced by ?

Answer 41

Produced by hot objects ( above 4000C) like the sun and is responsible for tanning the skin

Question 42

What are some uses of ultraviolet radiation ?

Answer 42

- Tanning beds - UV light sensor - Kills bacteria/ sterilises water

Question 43

What are the dangers of ultra violet radiation ?

Answer 43

- Certain wavelengths of ultraviolet can damage skin cells and lead to skin cancer - High energy UV rays are absorbed by cells and changes DNA codes when the cell replicates and cancer cells form

Question 44

What are 2 uses of X-rays ?

Answer 44

- medical imaging (bones) - security x-ray scanners

Question 45

What effect can x-rays have on the body ?

Answer 45

- X-rays damage cells, which may lead to cancer - X-rays are absorbed by the body and in large quantities can cause cancer

Question 46

How is Gamma produced ?

Answer 46

Gamma is produced by radioactive substances

Question 47

What are some uses of Gamma ?

Answer 47

- Sterilising medical equipment - Radio therapy - Sterilise food

Question 48

What effect can gamma rays have on the body ?

Answer 48

- Gamma rays can damage cells and cause cancer