Physics Topic 6 - Waves

Question 1

What are two types of waves?

Answer 1

1-transverse
2-longitudinal

Question 2

What is a transverse wave?

Answer 2

A wave for which the oscillations are perpendicular to the direction of energy transfer

Question 3

What is a longitudinal wave?

Answer 3

A wave for which the oscillations are parallel to the direction of energy transfer

Question 4

Give two examples of transverse waves

Answer 4

1-electromagnetic waves
2-seismic s-waves

Question 5

Give two examples of longitudinal waves

Answer 5

1-sound waves
2-seismic p-waves

Question 6

What are the parts of a longitudinal wave called?

Answer 6

Compressions and rarefactions

Question 7

What is a wave’s amplitude?

Answer 7

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

Question 8

What is a wavelength?

Answer 8

-the distance from a point on a wave to the same position on the adjacent wave
-most commonly peak to peak or trough to trough

Question 9

What is the frequency of the wave?

Answer 9

The number of waves that pass a given point each second

Question 10

What is the unit for frequency?

Answer 10

Hertz, Hz

Question 11

What is wave speed?

Answer 11

The speed at which the wave moves or at which energy is transferred through a medium

Question 12

What does a wave transfer?

Answer 12

Energy

Question 13

What word is used to describe when a wave bounces off a surface?

Answer 13

Reflection

Question 14

How do sound waves travel through a solid?

Answer 14

The particles in the solid vibrate and transfer kinetic energy through the material

Question 15

What is the frequency range of human hearing?

Answer 15

20 Hz - 20kHz

Question 16

What are ultrasound waves?

Answer 16

Waves which have a frequency higher that the upper limit of human hearing

Question 17

Give an example use for ultrasound waves

Answer 17

Medical or industrial imaging

Question 18

What natural event causes seismic waves to be produced? What types are produced?

Answer 18

-earthquakes
-they both produce p-waves and s-waves

Question 19

State a difference between the mediums that p-waves and s-waves can travel through

Answer 19

-p-waves travel through both solids and liquids
-s-waves only travel through solids

Question 20

What technique is used to detect objects in deep water and measure water depth?

Answer 20

-echo sounding
-high frequency sound waves are emitted, reflected and detected
-time difference between emission and detection, alongside wave speed, are used to calculate distances

Question 21

What type of spectrum do electromagnetic waves form?

Answer 21

A continuous spectrum

Question 22

Order the types of electromagnetic radiation from lowest to highest frequency

Answer 22

-radio waves
-microwaves
-infrared
-visible light
-ultraviolet
-x-rays
-gamma rays

Question 23

How do the speeds of EM radiation differ in a vacuum and in air?

Answer 23

Electromagnetic waves all travel at the same speed in a vacuum and in air

Question 24

What property of waves in different mediums causes refraction?

Answer 24

-velocity
-wave speed is slower in denser materials, causing refraction

Question 25

In which direction (relative tot he normal) do waves refraction when entering a denser medium?

Answer 25

-they bend towards the normal -the angle of refraction is less than the angle of incidence

Question 26

What types of waves can be produced by oscillations in an electrical current?

Answer 26

Radio waves

Question 27

How can radio waves create an alternating current in a circuit?

Answer 27

When radio waves are absorbed, they can induce oscillations in a circuit with the same frequency as the waves themselves

Question 28

Where do gamma rays originate from?

Answer 28

They originate from changes in the nuclei of atoms

Question 29

What health effects can ultraviolet waves cause?

Answer 29

-they can cause the skin to age prematurely -they can increase the risk of developing skin cancer

Question 30

What health effects can X-rays and gamma rays cause?

Answer 30

-they are ionising radiation so can cause mutations in genes -they can lead to increased risk of developing various cancers

Question 31

Give three practical uses for infrared radiation

Answer 31

1-electrical heaters 2-cooking food 3-infrared cameras

Question 32

Give two practical uses for microwave radiation

Answer 32

1-satellite communications 2-cooking food

Question 33

Give two practical uses for radio waves

Answer 33

1-television transmission 2-radio transmission

Question 34

What wave phenomenon is used by lenses to form an image?

Answer 34

Refraction

Question 35

How does a convex lens form an image?

Answer 35

Parallel rays of light are refracted and brought together at a point known as the principal focus

Question 36

What is meant by the focal length of a lens?

Answer 36

The distance from the lens to the principal focus

Question 37

What is the difference between the image produced by a concave and convex lens?

Answer 37

-convex lenses can produce real or virtual images -concave lenses can only produce virtual images

Question 38

Why does magnification not have a unit?

Answer 38

-it is the ratio between image height and object height -ratios do not require units

Question 39

What determine the colour of visible light waves?

Answer 39

The wavelength and frequency of the light waves

Question 40

What colour of visible light has the highest frequency?

Answer 40

Blue

Question 41

What colour of visible light has the largest wavelength?

Answer 41

Red

Question 42

What is meant by the term ‘secular reflection’?

Answer 42

Reflection from a smooth surface in a single direction

Question 43

What is meant by the term ‘diffuse reflection’?

Answer 43

Reflection from a rough surface which causes scattering

Question 44

How does a red colour filter work?

Answer 44

-a red filter absorbs all wavelengths of light other than those in the red range of the spectrum -this means only red light passes through the filter

Question 45

What determines the colour of an opaque object?

Answer 45

-different objects reflect different wavelengths of light by different amounts -the wavelengths that are most strongly reflected determine the colour

Question 46

What happens tot he wavelengths of light that aren’t reflected by an opaque object?

Answer 46

Any wavelengths that aren’t absorbed by the object

Question 47

What colour does an object appear if all wavelengths are reflected by equal amounts?

Answer 47

White

Question 48

What colour does an object appear if all wavelengths are absorbed?

Answer 48

Black

Question 49

What do all bodies emit and absorb?

Answer 49

Infrared radiation

Question 50

What happens tot eh quantity of infrared radiation emitted by an object as temperature increases?

Answer 50

The hotter the object, the more infrared radiation it will emit

Question 51

What is a perfect black body?

Answer 51

An object that absorbs all of the radiation that is incident upon it

Question 52

How much radiation does a perfect black body reflect or transmit?

Answer 52

None

Question 53

Why is a perfect black body the best possible emitter of radiation?

Answer 53

-it is a perfect absorber since it absorbs all radiation incident on it -a perfect absorber is also a perfect emitter

Question 54

Other than the intensity of radiation emitted, how does increasing the temperature of an object affect its emissions?

Answer 54

The wavelength distribution of any emission is dependent on the object’s temperature

Question 55

What can be said about the rates of emission and absorption for a body at constant temperature?

Answer 55

The body is absorbing and emitting radiation at the same time

Question 56

What can be said about the rates of emission and absorption for a body increasing in temperature?

Answer 56

The body is absorbing radiation faster than it is emitting it

Question 57

Give two factors that affect the temperature of the earth

Answer 57

1-the earth’s rate of absorption and emission of radiation 2-the amount of reflection of radiation into space