Waves (C11, C12)

Question 1

What are mechanical waves caused by?

Answer 1

An oscillating object

Question 2

D transverse wave

Answer 2

move away from the source and oscillates perpendicular to propagation

Question 3

What are longitudinal waves made up of

Answer 3

Compressions and rarefractions

Question 4

What is an example of a non-mechanical wave

Answer 4

EM radiation

Question 5

What do you have to be careful with wave graphs

Answer 5

The axis!

Question 6

Displacement v time graph

Answer 6

oscillator

Question 7

Displacement v position

Answer 7

Wave

Question 8

D wavelength

Answer 8

distance between two adjacent in phase points

Question 9

D period

Answer 9

time for one complete cycle or oscillation

Question 10

D frequency

Answer 10

number of wave cycles per second

Question 11

D Amplitude

Answer 11

Maximum displacement from the equilibirum position

Question 12

D Phase difference

Answer 12

Relationship between the patterens of oscillators

Question 13

D in phase

Answer 13

Pattern of oscillators are identical

Question 14

D anti phase

Answer 14

pattern of oscillation is opposite at any point

Question 15

What is a phasor

Answer 15

the circle that maps the curve that represents the wave

Question 16

How is intensity related to amplitude?

Answer 16

I is proportional to amplitude squared

Question 17

Four characteristics of wave behaviour

Answer 17

reflect
refract
diffract
interfere

Question 18

Difference between ray and wave front

Answer 18

Ray is direction of propagaation and wave front is a line connecting in phase points

Question 19

Angle of incidence = ?

Answer 19

Angle of reflection

Question 20

What is specular reflection/

Answer 20

Parrallel refelct at same angle

Question 21

D diffuse reflection

Answer 21

vaired normals means lots of angles

Question 22

Two special cases of refraction

Answer 22

Dispersion and Total internal refraction

Question 23

Why does refraction occur

Answer 23

change in medium
change in speed
change in wavelength
If angular if it speeds up bends away from normal and if it slows then it bends towards normal

Question 24

What type of wave doesn’t get faster in a higher density or depth?

Answer 24

Light (EM wave)

Question 25

What does a converging lens correct

Answer 25

long sightedness

Question 26

What does a diverging lens correct?

Answer 26

short sightedness

Question 27

What is n in waves?

Answer 27

refraction index c/v (therefore must be >=1)

Question 28

In total internal relfection what is special about the angle of incidence when the angle of reflection is 90 degrees

Answer 28

it is called the critical angle

Question 29

TIR occurs when

Answer 29

angle of incidence is greater than the critical angle

Question 30

What law relations refractive index

Answer 30

snells law n1sin01 = n2sin02

Question 31

Why does dispersion occur?

Answer 31

different frequencies refract different amounts due to their different speeds

Question 32

What colour refracts the least

Answer 32

red

Question 33

What causes diffraction

Answer 33

Wave passing through a gap

Question 34

d>>lambda

Answer 34

little diffraction

Question 35

d=lambda

Answer 35

noticable diffraction (some straight parts)

Question 36

d << lambda

Answer 36

strong diffraction (big curves)

Question 37

What is an EM wave made of?

Answer 37

Electric and magnetic fields

Question 38

What are teh three types of UV and what are their characteristics?

Answer 38

UVA - tanning, destroys collagen UVB - burns, cancer and vit D UVC - broken down by ozone

Question 39

What is polarisation?

Answer 39

When all oscillations of a field are limited to one plane only (electric field)

Question 40

Name two ways of polarised waves coming about

Answer 40

Production | Filter

Question 41

When does a grill block EM radiation

Answer 41

Parallel grill and wave

Question 42

What law links amplitude and intensity

Answer 42

Malus's law

Question 43

What happens when two waves meet?

Answer 43

They SUPERPOSE

Question 44

What is constructive interference?

Answer 44

The superposition of two waves in phase such that the resultant displacement is greater than either of the initial displacements

Question 45

Destructive interference

Answer 45

Superposition of two waves in antiphase such that the resultant displacement is zero

Question 46

What is the principle of superposition

Answer 46

Total displacement = vector sum of the displacements of each wave at that point

Question 47

What makes two sources coherant?

Answer 47

Whether they produce a stable interference pattern, i.e have a constant phase difference

Question 48

What is the central line between two sources called?

Answer 48

Central maximum

Question 49

What is path difference?

Answer 49

difference in distance to point of intereference from each source

Question 50

What are other maxima called?

Answer 50

Subsidary maxima (1st order than 2nd order etc)

Question 51

path difference for desttrucutive interference?

Answer 51

(n=1/2)*lambda

Question 52

path difference for constructive interference?

Answer 52

n*lambda

Question 53

Where is n counted from in path difference/

Answer 53

central maxima

Question 54

What are characteristics of coherant sources?

Answer 54

Same frequency and constant phase difference

Question 55

What has to be true about the young's double slit equation?

Answer 55

The slit separation has to be much much smaller than the distance between the source and the interference pattern

Question 56

What type of light is used in the Young's double slit experiment?

Answer 56

monochromatic (laser or bulb passed through a filter)

Question 57

double slit - What happens when one slit is wider than the other?

Answer 57

No points of destructive intereference

Question 58

What happens with double slit of white light? colour order?

Answer 58

Colours interefere and diffract different amounts | white in middle and then spectrums with violet coloses to centre and red furthest away

Question 59

How is a stationary wave made?

Answer 59

Two indentical waves travelling in opposite directions

Question 60

2 methods of making a stationary wave?

Answer 60

send tow waves at each other | 1 wave source that reflects

Question 61

What is a point of amplitude zero called on a stationary wave/

Answer 61

Node

Question 62

What is an antinode?

Answer 62

Point on a stationary wave that vibrates with maximum energy and amplitude

Question 63

Where is max KE on a stationary wave

Answer 63

When an antinode is flat

Question 64

Where is in phase on a stationary wave?

Answer 64

Between nodes

Question 65

Where is antiphase on a stationary wave?

Answer 65

either side of a node

Question 66

What doesn't matter for phase difference?

Answer 66

displacement

Question 67

What is the first stationary wave known as?

Answer 67

fundamental mode of oscillation (f0)

Question 68

What's the best way to understand a stationary wave question?

Answer 68

sketch

Question 69

What is an open end of a tude

Answer 69

antinode

Question 70

What is a closed end

Answer 70

node

Question 71

What type of wave is in a stationary wave tube

Answer 71

longitudinal wave