Waves and Radiation Flashcards
(140 cards)
1
Q
waves transfer ____
A
energy from one place to another
2
Q
types of wave
A
longitudinal and transverse
3
Q
transverse wave
A
particles move perpendicular to the direction of travel of the wave
(remember slinky)
can travel through a medium or a vacuum
4
Q
example of transverse wave
A
basically anything (EM spectrum)
5
Q
longitudinal wave
A
particles move parallel to the direction of travel (remember slinky)
cannot travel through a vacuum
6
Q
example of longitudinal wave
A
sound wave
7
Q
trough
A
the lowest point of the wave
8
Q
crest
A
the highest point of the wave
9
Q
equilibrium position
A
the rest position of the wave
10
Q
amplitude
A
the vertical distance from the equilibrium position to either the crest or the trough. measured in metres ( loudness)
11
Q
wavelength
A
the horizontal distance between the same point in consecutive waves. measured in metres
12
Q
period
A
time taken for one complete wave to pass a particular point
13
Q
wave speed
A
distance the wave travels each second
14
Q
frequency
A
number of waves per second that passes a particular point (pitch)
15
Q
relationship for calculating frequency
A
f= N/t
16
Q
relationship for calculating speed of wave w wavelength and frequency
A
v = f x wavelength
17
Q
relationship for calculating period
A
T = 1/f
18
Q
relationship for calculating wavelength
A
wavelength= d/N
19
Q
relationship for calculating wave speed
A
v= d/t
20
Q
diffraction
A
the effect of waves bending when they meet obstacles
21
Q
diffraction effect____ as wavelength ___ or as gap width ___
A
increases, increases, decreases
22
Q
shorter wavelengths do/ do not diffract as much as longer ones
A
do not
23
Q
sound waves _____ travel through a vacuum
A
cannot
24
Q
sound waves are created by
A
vibrations
25
oscilloscope
a machine that analyses sound waves. amplitude and frequency are examined
26
on an oscilloscope, changing the frequency or pitch means that
more or less waves will be displayed
27
on an oscilloscope, changing the amplitude or loudness of the signal
changes the vertical height of the trace on the screen
28
speed of light in air
3.0 x10 to the power of -8 ms-1
29
speed of sound in air
340 ms-1
30
what is faster, sound or light
light
31
measuring speed of sound experiments-
1- pistol and stopwatch (v =d/t)
2- pistol and stopwatch w wall (v=half d/t)
3- hammer, electronic timer, metal plate, microphones (start and stop)
32
range of human hearing
20-20,000 Hz
33
ultrasounds
high frequency vibrations beyond human hearing
34
uses for ultrasound
cleaning instruments
scanning unborn children in the womb
measuring blood flow through the heart
detecting kidney stones
35
sonar
detecting the depth of water
the device emits a series of ultrasound pulses and these are reflected by the sea bed and travel back towards the boat and are received by the sonar device. (2d=vt)
36
speed of sound in water
1500ms-1
37
musical instruments produce sound by
causing vibrations to pass through the air- membrane, string, air or reed
38
sound produced by a loudspeaker or headphones is produced by
a small current passing through a coil wire which becomes and electromagnet. this interacts w a permanent magnet to produce a movement of the cone which matches the fluctuations in the current.
39
loudness of a sound is measured in
decibels (dB)
40
sound levels above _____ can be dangerous
85dB
41
ACN
active noise cancellation- a method for reducing unwanted sound by the addition of a second sound specifically designed to cancel the first
42
all waves in the EM spectrum are
transverse
43
all waves in the EM spectrum travel at
3.0 x10 to the power of 8ms-1
44
the higher the frequency of the wave=
the more energy they carry
45
order of EM spectrum from long wavelength to short wavelength/ low frequency to high frequency
```
radio waves
microwaves
infrared
visible light
ultraviolet rays
X rays
gamma rays
```
46
the energy transferred by these waves is related to their
frequency
47
wavefronts=
crests
48
distance between consecutive wavefronts =
wavelength
49
ray=
indicates direction of energy transfer, drawn perpendicular to the wavefront and has an arrow
50
reflection
when a wave encounters a boundary between 2 different mediums it experiences reflection
51
incident ray
ray approaching the boundary between 2 mediums
52
reflected ray
ray reflected away from the boundary between 2 mediums
53
angle of incidence
angle between normal and incident ray
54
angle of reflection
angle between normal and reflected ray
55
normal
dotted line drawn perpendicular to the boundary between 2 different mediums
56
refraction
a change in speed and wavelength . frequency stays the same. change in speed affects a change in direction
57
when does refraction occur
when a wave experiences a change in medium at an angle of incidence that is greater than 0 degrees
58
angle of refraction
angle between normal and refracted ray
59
if the angle of incidence is greater than the refracted ray the ray refracts ___ the normal
towards (low density to high density)
60
if the incidence ray is less than the refracted ray the ray refracts _____ the normal
away from (high density to low density)
61
converging (convex)
bring parallel rays of light to a focus
62
diverging (concave)
cause parallel rays of light to spread out
63
correcting long sight
add a convex or converging lense to enable them to focus the rays on to the retina
line don’t touch and go dotted out of the eye
64
correcting short sight
add a diverging or concave lense to enable the rays to focus onto the retina
lines cross
65
critical angle
angle of incidence that produced an angle of refraction if 90 degrees
66
angle of incidence less than critical angle
refraction
67
total internal reflection
angle of incidence greater than critical angle
68
only get critical angle in
refraction
69
principle of reversibility
if direction of a ray is reversed it will follow the same path
70
applications of TIR
fibre optics- the use of thin layers of glass/ other transparent solids to transmit light
71
periscope
an apparatus consisting of a tube attached to a set of mirrors or prisms, by which an observer can see things that are otherwise out of sight.
72
properties of electron
relative mass- 0
| relative charge- -1
73
properties of proton
relative mass- 1
| relative charge- +1
74
properties of neutron
relative mass- 1
| relative charge- 0
75
relative mass or charge of an atom is calculated by
adding all the relative masses and charges of the particles together
76
relative charge of an atom is always
0, no overall charge, neutral
77
number of neutrons=
mass number- protons
78
atomic number=
protons (electrons)
79
mass number on ____, atomic number on ____
top, bottom
80
isotopes
different number of neutrons (mass number) same number of protons (atomic number)
81
unstable atoms are usually ____
man made
82
unstable isotopes become stable by
shedding mass and emitting energy
83
radioactive decay
unstable isotopes becoming stable by releasing different types of particles
84
ionisation
the gain or loss of an electron from an atom to produce a charged atom (an ion)
85
loses an electron =
positive ion
86
gains an electron=
negative ion
87
types of energy that can be emitted
alpha particle
beta particle
gamma ray
88
alpha particle
relative charge : +2
relative mass : 4
very large in mass
very positive
equal to a helium nucleus
89
beta particle
fast moving electron emitted from nucleus
relative charge: -1
relative mass: 0
neutron changes into proton and electron- making beta decay
90
gamma
no mass
no charge
high f, short wavelength
lots of energy
91
activity
the number of nuclei that undergo radioactive decay per second.
measured in bequerels Bq
A= N/t
92
safety
T- time
D- distance
S- shielding
93
background radiation
radiation that exists in our immediate environment at all times
94
critical angle
angle of incidence that produced an angle of refraction if 90 degrees
95
angle of incidence less than critical angle
refraction
96
total internal reflection
angle of incidence greater than critical angle
97
only get critical angle in
refraction
98
principle of reversibility
if direction of a ray is reversed it will follow the same path
99
applications of TIR
fibre optics- the use of thin layers of glass/ other transparent solids to transmit light
100
periscope
an apparatus consisting of a tube attached to a set of mirrors or prisms, by which an observer can see things that are otherwise out of sight.
101
properties of electron
relative mass- 0
| relative charge- -1
102
properties of proton
relative mass- 1
| relative charge- +1
103
properties of neutron
relative mass- 1
| relative charge- 0
104
relative mass or charge of an atom is calculated by
adding all the relative masses and charges of the particles together
105
relative charge of an atom is always
0, no overall charge, neutral
106
number of neutrons=
mass number- protons
107
atomic number=
protons (electrons)
108
mass number on ____, atomic number on ____
top, bottom
109
isotopes
different number of neutrons (mass number) same number of protons (atomic number)
110
unstable atoms are usually ____
man made
111
unstable isotopes become stable by
shedding mass and emitting energy
112
radioactive decay
unstable isotopes becoming stable by releasing different types of particles
113
ionisation
the gain or loss of an electron from an atom to produce a charged atom (an ion)
114
loses an electron =
positive ion
115
gains an electron=
negative ion
116
types of energy that can be emitted
alpha particle
beta particle
gamma ray
117
activity (A)
the number of nuclei that undergo radioactive decay each second
118
activity is measured in
bequerels Bq
119
relationship for finding activity
A= N/t
120
background radiation
radiation that exists in our immediate environment at all times
121
count rate is measured by
geiger- muller tube
122
count rate measures
how much radiation is present (including background radiation which needs to be corrected)
123
ionisation density
measure of ionisations occurring in a set volume of space per unit time
124
alpha particles are the _______ harmful
most
125
absorbed dose (D)
energy per unit mass
126
relationship for absorbed dose
D= E/m
127
absorbed dose is measured in
Grays (Gy)
128
biological damage depends on
T ype of radiation (a, B, gamma)
A bsorbed dose received
P art of body (organ or tissue) exposed
129
radiation weighting factor
the ionising density and biological effects
(found on data sheet)
alpha 20
beta 1
gamma 1
130
equivalent dose (H)
the product of absorbed dose and radiation weighting factor
131
equivalent dose is measured in
sieverts (Sv)
132
relationship for equivalent dose
H= D x radiation weighting factor
133
equivalent dose rate
equivalent dose per unit time (H with dot over it)
134
relationship for equivalent dose rate
H (with dot over) = H/t
135
what is half life
time taken for the activity of the radioactive source to reduce to half its original value
136
relationship method 2 for half life
Ao= A x 2n (squared)
137
activity time curve
how the activity of a source changes over time (exponential decay)
138
nuclear fission
when a neutron collides with a large unstable nucleus which causes it to split into two smaller nuclei and release heat energy and a few neutrons
139
nuclear fusion
two small nuclei collide and join together to make a larger nucleus causing heat energy to be released
occurs in the sun
140
chain reaction
the released neutrons go on to produce further fission reactions
used in nuclear reactors
