Waves And The Electromagnetic Spectrum T2

Question 1

What happens when waves travel through a medium?

Answer 1

The particles of the medium vibrate and transfer energy and information between each other

Question 2

What is the amplitude of a wave?

Answer 2

The amplitude of a wave is the displacement from the rest position

Question 3

What is the wavelength?

Answer 3

The wavelength is the length of a full cycle of the wave

Question 4

What is the frequency of a wave?

Answer 4

Frequency is the number of complete cycles of the wave passing a certain point per second. Frequency is measured in hertz. 1Hz is 1 wave per second

Question 5

What is the period of a wave?

Answer 5

The period of a wave is the number of second needed to compete 1 cycle. Period = 1 / frequency

Question 6

What are transverse waves?

Answer 6

In transverse waves, the vibrations are perpendicular to the direction the wave travels. Most waves are transverse

Question 7

What are longitudinal waves?

Answer 7

In longitudinal waves, the vibrations are parallel to the direction the wave travels

Question 8

How do you calculate wave speed?

Answer 8

Wave speed = frequency x wavelength

Question 9

What happens when a wave is absorbed?

Answer 9

The wave transfers the energy to the materials energy stores. Often the energy is transferred to the thermal energy

Question 10

What happens when a wave is transmitted?

Answer 10

The wave carries on traveling through the new material.

Question 11

What happens when a wave is reflected?

Answer 11

This is where the incoming rays are neither absorbed or transmitted, but instead sent back

Question 12

What happens in refraction?

Answer 12

Waves travel at different speeds in materials with different densities, so when a wave crosses a boundary between materials it changes speed, if the wave hits the boundary at an angle, this causes a change of direction - refraction

Question 13

How are sound waves caused?

Answer 13

By vibrating objects. These vibrations passed through the surrounding medium as a series of compressions and refractions

Question 14

How do you hear sound?

Answer 14

Sound waves that reach you eardrum cause it to vibrate, these vibrations are past on to tiny bones in you ear called ossiles, through semi circular canals, and to the cochlea. Te cochlea turn these vibrations into electrical signals to the brain

Question 15

What is ultrasound?

Answer 15

Ultra sou d is sound with frequencies higher than 20000Hz

Question 16

How can ultrasound be used?

Answer 16

Medical imaging. Ultrasound waves can pass through the body , but when they reach a boundary between 2 mediums, such as fluid in the womb and the foetus, some pf the wave is reflected and detected.

Question 17

What is infrasound?

Answer 17

Infrasound is sound with frequencies lower than 20Hz

Question 18

What are p-waves?

Answer 18

they are seismic waves. P-waves are longitudinal, they travel through solids and liquids, they are faster than s-waves

Question 19

What are s-waves?

Answer 19

S-2aves are transverse and only travel through solids, they’re slower than p-waves

Question 20

What is the law of reflection?

Answer 20

Angle of incidence = angle of reflection

Question 21

What is specular reflection?

Answer 21

Specular reflection is when waves are reflected in one direction by a smooth surface. This means you get a clear reflection like a mirror

Question 22

What is diffuse reflection?

Answer 22

Diffuse reflection occurs when waves are reflected in all directions by a rough surface

Question 23

What is white light?

Answer 23

White light is a mixture of all the different colours of light which all have different wavelengths

Question 24

What are opaque objects?

Answer 24

Opaque objects do not transmit light, they absorb some wavelengths of light but reflect others and so they are the colour they reflect

Question 25

What are transparent and translucent materials?

Answer 25

Objects which transmit light, not all light that hits the surface is absorbed or reflected, some pass through

Question 26

What is a converging lens?

Answer 26

A converging lens bulges outwards in the middle. It causes parallel rays of light to be together at the principle focus

Question 27

What is a diverging lens?

Answer 27

A diverging lens caves inwards. It causes parallel rays of light to spread out

Question 28

What type of waves are electromagnetic waves?

Answer 28

Electromagnetic waves are transverse waves, they all travel at the same speed in a vaccum

Question 29

What is the wavelength of radio waves?

Answer 29

10^4

Question 30

What happens when there is a higher frequency of an EM wave?

Answer 30

The more energy it transfers so the more dangerous it is

Question 31

How does radiation affect the earth’s temperature?

Answer 31

During the day, lots of radiation is transferred to the earth from the sun, some of this is reflected, but most of it is absorbed, the radiation is reflected and absorbed by the atmosphere, clouds and the surface

Question 32

What are radio waves primarily used for?

Answer 32

Radio waves are primarily used for communication and broadcasting

Question 33

What are microwaves used for?

Answer 33

Communication and cooking

Question 34

What is infrared radiation used for?

Answer 34

Infrared radiation is used to increase or monitor temperature, it can also transfer infomation

Question 35

How does photography work?

Answer 35

Photographic film reacts to light to form an image, digital cameras contain image sensors, which detect visible light and generate an electrical signal

Question 36

What is ultraviolet used for?

Answer 36

Security pens and long life lights

Question 37

What are x rays used for?

Answer 37

X rays let us see inside things, they can be used to see the internal structure of objects

Question 38

What are gamma rays used for?

Answer 38

They are used for sterilising things such as medical equipment - they kill microbes