P2- Waves

Question 1

What are the two types of waves?

Answer 1

Transverse and longitudinal

Question 2

What type of vibration do transverse waves have?

Answer 2

Sideways oscillations that are perpendicular (at 90 degrees) to the direction of energy transfer

Question 3

What are some examples of transverse waves?

Answer 3

Most waves
Electromagnetic waves
Ripples and waves in water
A wave on a string

Question 4

What type of vibrations do longitudinal waves have?

Answer 4

Oscillations that are parallel to the direction of energy transfer

Question 5

What are some examples of longitudinal waves?

Answer 5

Shock waves in the air (ultrasound)
Shock waves such as some seismic waves

Question 6

Which direction do waves transfer energy in?

Answer 6

The direction that they are travelling

Question 7

What is the amplitude of a wave?

Answer 7

The maximum displacement of a point on the wave from its undisturbed position

Question 8

What is the wavelength of a wave?

Answer 8

The distance between the same point on two adjacent waves such as between the trough of one wave and the trough of the wave next to it

Question 9

What is the frequency of a wave?

Answer 9

The number of complete waves passing through a certain point per second

Question 10

What is frequency measured in?

Answer 10

Hertz or Hz
1 Hz is 1 wave per second

Question 11

What is the period of a wave?

Answer 11

The amount of time it takes for a full cycle of the wave

Question 12

How do you find the period of a wave?

Answer 12

T (Period) = 1/f (Frequency)

Question 13

What is wave speed?

Answer 13

The speed at which energy is being transferred or the speed the wave is moving at

Question 14

What is the equation for wave speed?

Answer 14

Wave speed = Frequency x Wavelength

Question 15

What three things can happen when a wave arrives at a boundary between two different materials?

Answer 15

They can be absorbed by the material, transmitted through the material or reflected off the material

Question 16

What happens when a wave is absorbed at a boundary?

Answer 16

The wave is absorbed by the material, this transfers energy to the materials energy stores, this is how a microwave works

Question 17

What happens when a wave is transmitted at a boundary?

Answer 17

The waves are transmitted meaning they keep on travelling through the new material which often leads to refraction

Question 18

What is the rule when a wave is reflected at a boundary?

Answer 18

Angle of incidence = Angle of reflection

Question 19

What are the two types of reflection?

Answer 19

Specular and diffuse

Question 20

What is the difference between specular and diffuse reflection?

Answer 20

Specular is when a wave is reflected in a single direction by a smooth surface whilst diffuse is when a wave is reflected by a rough surface and scatters in lots of different directions

Question 21

Can you list the EM wave spectrum in order?

Answer 21

Radio waves
Micro waves
Infra red
Visible light
Ultra violet
X rays
Gamma rays

Question 22

What increases and decreases as you go along the EM wave spectrum?

Answer 22

Frequency increases and wavelength decreases

Question 23

How do the speeds of EM waves vary?

Answer 23

They all travel at the same speed through air or a vacuum

Question 24

What is refraction?

Answer 24

Waves changing directions at a boundary

Question 25

What are radio waves used for?

Answer 25

Communications such as bluetooth and the radio

Question 26

What are microwaves used for?

Answer 26

Satellites and microwave ovens

Question 27

What is infrared used for?

Answer 27

To increase temperature Cooking To monitor people through temperature

Question 28

What is visible light used for?

Answer 28

Transmitting data

Question 29

What is ultraviolet used for?

Answer 29

Tanning beds Fluorescent lights

Question 30

What are X and Gamma rays used for?

Answer 30

Radiography to take pictures of bones Radio or chemotherapy Medical tracers

Question 31

How do doctors protect themselves from X and Gamma rays?

Answer 31

Lead aprons Lead screens Leaving the room

Question 32

How is UV harmful?

Answer 32

Can cause skin cancer

Question 33

How are X and Gamma rays harmful?

Answer 33

Ionising radiation can cause gene mutation or cell destruction and cancer

Question 34

Why can UV, X rays and Gamma rays be harmful?

Answer 34

They are high frequency waves so they transfer a lot of energy

Question 35

What are the primary colours of light?

Answer 35

Pure red, green and blue

Question 36

What happens when all the colours of light are put together?

Answer 36

It creates white light

Question 37

What happens when light hits an opaque object?

Answer 37

They do not transmit light, when visible light waves hit them they absorb some wavelengths of light and reflect others

Question 38

Why are some opaque objects primary colours?

Answer 38

Which wavelengths of light are most strongly reflected, a red apple is red, because red is the most reflected

Question 39

Why are some opaque objects non primary colours?

Answer 39

The light most strongly reflected is that colour or colours mix to make that colour

Question 40

Why are some opaque objects white?

Answer 40

They reflect all wavelengths of visible light equally

Question 41

Why are some opaque objects black?

Answer 41

They absorb all wavelengths of visible light

Question 42

What do transparent and translucent objects do when light hits them?

Answer 42

They transmit light, not all light that hits the surface is absorbed or reflected, some can pass through the object

Question 43

What do colour filters do?

Answer 43

They only let through particular wavelengths and filter out others so only certain colours are transmitted

Question 44

What happens if white light is shone at a blue colour filter?

Answer 44

Only blue light is transmitted and the rest is absorbed

Question 45

What happens if red light is shone at a blue colour filter?

Answer 45

It is not transmitted so the object behind it appears black

Question 46

What happens to infrared emitted when an object is hotter than its surroundings?

Answer 46

More is emitted than is absorbed as it cools down

Question 47

What infrared is emitted when an object is at a constant temperature?

Answer 47

The radiation is emitted at the same rate it is absorbed

Question 48

What colours and textures are better at absorbing and emitting infrared?

Answer 48

Black is better than white and matt is better than shiny

Question 49

What is a black body?

Answer 49

An object that absorbs all of the radiation that hits it, no radiation is reflected or transmitted,it is the ultimate emitter

Question 50

How does radiation affect the Earths temperature?

Answer 50

During the day lots of light radiation is transferred from the sun and absorbed causing a temperature increase

Question 51

What causes sound waves?

Answer 51

Vibrating objects

Question 52

Why can't sound waves travel in space?

Answer 52

Because it's mostly a vacuum meaning there are no particles to move or vibrate

Question 53

How do you hear sound?

Answer 53

Sound waves reach your eardrum causing it to vibrate, the vibrations are passed on to bones in your ear called ossicles, through the semicircular canals and to the cochlea where the vibrations are turned into electrical signals which are sent to your brain

Question 54

When are sound waves reflected and refracted?

Answer 54

Reflected by hard surfaces and refracted as they enter different media such as speeding up in denser materials