Physics :)

0.0(0)
studied byStudied by 0 people
learnLearn
examPractice Test
spaced repetitionSpaced Repetition
heart puzzleMatch
flashcardsFlashcards
Card Sorting

1/238

flashcard set

Earn XP

Description and Tags

Study Analytics
Name
Mastery
Learn
Test
Matching
Spaced

No study sessions yet.

239 Terms

1
New cards
Protons natural effect on each other is that they
repel each other
2
New cards
A proton's quark configuration is
Up, Up, Down (uud)
3
New cards
The charge of a proton is positive because
The sum of its quark's charges \= 1
u \= +2/3
d \= -1/3
Configuration \= uud \= 2/3 + 2/3 - 1/3 \= 3/3 \= 1
4
New cards
The charge of a pion is positive because
The sum of its quark's charges \= 1
u \= +2/3
d^-(anti-down quark) \= 1/3
Configuration \= ud^- \= 2/3 + 1/3 \= 3/3 \= 1
5
New cards
The charge of a neutron is neutral because
The sum of its quark's charges \= 0
u \= +2/3
d \= -1/3
Configuration \= udd \= 2/3 - 1/3 - 1/3 \= 0/3 \= 0
6
New cards
An atom contains
- a positively charged nucleus composed of protons and neutrons.
- electrons that surround the nucleus
7
New cards
A nucleon is
a proton or neutron in the nucleus
8
New cards
Each electron has
a negative charge
9
New cards
The electrons are held in the atom by
the electrostatic force of attraction between the negatively charged electrons and the nucleus, due to the protons giving the nucleus a positive charge
10
New cards
The nucleus is ? times the size of the atom
0.00001
(one ten thousandth)
11
New cards
The charge of a particle is shown in
Coulombs (C)
12
New cards
The mass of a particle is measured in
Kilograms (kg)
13
New cards
An electron has ? compared to a proton
- much less mass
- opposite charge
14
New cards
A similarity between protons and neutrons is
their almost equal mass
15
New cards
Neutrons are
uncharged
16
New cards
An electron has a mass ? times smaller than a proton
2000
17
New cards
Atoms of the same ? (with the same number of ?) that have different numbers of ? are called ?
Atoms of the same *element* (with the same number of *protons*) that have different numbers of *neutrons* are called *isotopes*
18
New cards
Isotopes are
atoms with the same number of protons and a different number of neutrons
19
New cards
The total number of protons and neutrons in an atom is called
the
nucleon number / mass number
20
New cards
Each type of nucleus is called
a nuclide
21
New cards
The specific charge of a charged particle \=
charge / mass
22
New cards
A stable isotope has ? that do not ? so there must be ?. We call this the ? because it overcomes the ? between ?, keeping them together.
A stable isotope has *nuclei* that do not *disintegrate* so there must be *a force holding them together*. We call this the *strong nuclear force* because it overcomes the *electrostatic force of repulsion* between *protons and neutrons*, keeping them together.
23
New cards
10^-15 \=
femto - fm
24
New cards
The electrostatic force between two charged particles has ? range but ?
The electrostatic force between two charged particles has *infinite* range but *the force decreases as the range increases*
25
New cards
The strong force is (range)
Attractive from 4fm to 0.5fm
Closer than 0.5fm it becomes repulsive
26
New cards
In Young's double slit experiment:

d is ?

s is ?

Theta is ?

D is?

w is ?
d is gap separation

s is also gap separation

Theta is the angle from n \= 0 to n \= x

D is the distance from the gaps to the screen

w is the fringe spacing
27
New cards
What's the name given to a maximum on a standing wave
An antinode
28
New cards
For the first harmonic, in terms of length: wavelength \=
2 L
29
New cards
The nth harmonic has length L given by
L \= (n/2)wavelength
30
New cards
Points either side of the rest position in a standing wave are ?(phase)
180 degrees out of phase / antiphase
31
New cards
Points on the same side of the equilibrium position on a stationary wave are?(phase)
In phase
32
New cards
A progressive wave is
a wave that moves through the medium
33
New cards
When two waves meet they
Superpose
34
New cards
The frequency of the nth harmonic is given by
n * fundamental frequency
35
New cards
If the frequency of the first harmonic is 20Hz, the third has f \=
60Hz
36
New cards
When labeling standing waves, antinodes are labeled ? and nodes are labeled ?
Antinodes : A

Nodes : N
37
New cards
Longitudinal waves differ from transverse in that
points on the wave oscillate in line with the direction the wave travels.
38
New cards
Two points on a progressive wave are one-eighth of a wavelength apart. The distance
between them is 0.5 m, and the frequency of the oscillation is 10 Hz. What is the minimum
speed of the wave?
40 m/s

Because
if λ / 8 \= 0.5
λ\= 4
v \= fλ
v \= 10 * 4 \= 40 m/s
39
New cards
The speed of sound in water is 1500 m s−1. For a sound wave in water having frequency
2500 Hz, what is the minimum distance between two points at which the vibrations are
𝜋/3 rad out of phase?
0.1 m

v \= fλ
v / f \= λ
1500 / 2500 \= λ \= 0.6 m
λ \= 2𝜋
𝜋/3 \= λ/6
𝜋/3 \= 0.6 / 6 \= 0.1 m
40
New cards
A source emits light of wavelength 600 nm as a train of waves lasting 0.01 μs. How many complete waves are sent out?
speed of light \= 3 × 108 m/s
5 * 10^6

v \= fλ
v / λ \= f
(3 * 10^8) / (600 * 10^-9) \= f \= 5 * 10^14
If a clock ticks once a seconds then to find the number of ticks every half a second: 1 * 1/2 \= 1/2 ticks per second

So (5 * 10^14) * (0.01 * 10^-6) \= number of waves \= 5 * 10^6
41
New cards
A progressive wave in a stretched string has a speed of 20 m s−1 and a frequency of 100Hz. What is the phase difference between two points 25 mm apart?
v \= fλ
v / f \= λ
20 / 100 \= λ \= 0.2 m
25 * 10^-3 \= 0.025 m
0.2 / 0.025 \= 8
So the phase difference is an eight of a wavelength
or 2pi/8 \= pi/4 radians
42
New cards
Monochromatic light passes from air into water. The ? change but not the ?
The velocity and wavelength change but not the frequency
43
New cards
The least distance between two points of a progressive transverse wave which have a phase difference of 𝜋3 rad is 0.050 m. If the frequency of the wave is 500 Hz, what is the speed of the wave?
150 m/s

pi / 3 \= 0.05 m
2pi \= λ
pi \= 0.15
2pi \= 0.3 \= λ
v \= fλ
v \= 500 * 0.3 \= 150 m/s
44
New cards
State the characteristic features of longitudinal waves
particle vibration (or disturbance or oscillation) (1) same as (or parallel to) direction of propagation (or energy transfer) (1)
45
New cards
State the characteristic features of transverse waves
(particle vibration) perpendicular to direction of propagation (or energy transfer) (1)
46
New cards
Explain how energy is transmitted in a sound wave.
particles in the transmitting medium are made to vibrate/given energy

or mention of a compression/region of increased pressure (or rarefaction) cause nearby particles to vibrate/have energy/move

or the compression produces a compression further along (the medium)

2
47
New cards
Define the amplitude of a wave.
maximum displacement from equilibrium/mean position/mid-point/etc (1)
48
New cards
Give examples of transverse waves
electromagnetic radiation (1)
surface of water/water waves/in ripple tank (1)
rope (1)
slinky clearly qualified as transverse (1)
secondary ('s') waves (1)
49
New cards
Differences between transverse and longitudinal waves
transverse wave: oscillation (of medium) is perpendicular to wave travel
or transverse can be polarised
or all longitudinal require a medium
50
New cards
Explain what is meant by the frequency of a wave.
number of (complete) waves (passing a point) in 1 second OR
number of waves / time (for the waves to pass a point)
OR
(complete number of) oscillations \ vibrations per second
OR
1 / T with T defined as time for 1 (complete) oscillation
51
New cards
A continuous ultrasound wave of constant frequency is reflected from a solid surface and returns in the direction it came from.
Assuming there is no significant loss in amplitude upon reflection, describe and explain the effect the waves have on the particles in the medium between the transmitter and the solid surface.
• mention of nodes and antinodes
• particles not moving at a node
• maximum displacement at antinode
• particles either side of node in antiphase / between two nodes in phase
• variation of amplitude between node
52
New cards
Any process of creating ions is called
ionisation
53
New cards
?, ? and ? create ions when they pass through atoms
Alpha, beta and gamma radiation
54
New cards
? passing through a ? tube create ions with they collide with vapour in the tube
Electrons passing through a fluorescent tube create ions with they collide with vapour in the tube
55
New cards
An electron that moves through a potential difference of 2000V is ?eV
2000eV
56
New cards
An ion of charge +2e moves though a potential difference of 10V is ?eV
20
57
New cards
Atoms can absorb energy from colliding electrons without being ionized via
excitation
58
New cards
The energy values at which an atom absorbs energy are its
excitation energies
59
New cards
The lowest energy of an atom is called its
ground state
60
New cards
Excitation energy measurements are used to construct
an energy level diagram for the atom
61
New cards
When electrons move down an energy level a ? which is called ?
When electrons move down an energy level a photon is emitted which is called de-excitation
62
New cards
Acceleration of free fall is
The acceleration of an object acted on only by the force of gravity
63
New cards
Alpha radiation is
Particles that consist of two protons and two neutrons
64
New cards
A point on a stationary wave moves
up and down either side of the rest position / equilibrium position
65
New cards
Two points on a stationary wave, one either side of the rest position, have the phase relationship:
180 degrees out of phase
66
New cards
Two points on a stationary wave that are the same side of the rest position are
in phase
67
New cards
Halfway between two nodes is a
antinode
68
New cards
On a stationary wave, if L is 0.48m what is the wavelength?
0.96m
wavelength \= twice the distance between two nodes / antinodes
where L is the distance between two nodes / antinodes
69
New cards
Stationary waves:
Equation to find frequency of nth harmonic
f \= (n * c) / 2L
70
New cards
A guitarist wants to increase the fundamental frequency of his strings, how might he do it?
Increase the tension
71
New cards
Define: fundamental frequency
the frequency of the first harmonic
72
New cards
frequency is
the number of full wave cycles per second
73
New cards
in longitudinal wave, points on the wave
oscillate in the axis of the wave's direction of travel
74
New cards
Total internal reflection occurs when
the angle of incidence is greater than the critical angle
75
New cards
equation for a wave passing between two materials, involving their refractive index and angles
n1 * sinANGLE1 \= n2 * sinANGLE2
76
New cards
The critical angle is found using the equation:
n1 * sinANGLEc \= n2 * sin90
Where ANGLEc is the critical angle, being reflected 90 degrees
77
New cards
An emitted photon has energy 9.92 * 10-19 J
Calculate its wavelength
frequency \= E / h
wavelength \= c / f
so
wavelength \= c / E / h
wavelength \= ch / E
wavelength \= ((3 * 10^8) * (6.63 * 10^-34))/(9.92 * 10^-19)
wavelength \=
78
New cards
An electron with no excess energy is in ? state
An electron with some excess energy is in ? state
An electron with enough excess energy to leave an atom is in ? state
An electron with no excess energy is in its ground state (n \= 1)
An electron with some excess energy is in an excited state
An electron with enough excess energy to leave an atom is in an excited state (n \= infinite)
79
New cards
Work function equation
80
New cards
Intensity of light is
the number of photons striking a surface per second
81
New cards
What is the work function equal to?
the minimum energy required for an electron to be removed from a cold atom with 0 kinetic energy
82
New cards
In the work function what is Ek?
The maximum amount of kinetic energy has after escaping an atom
83
New cards
What kind of experiment would confirm that electrons have wave-like nature?
diffraction (through an atomic lattice)
84
New cards
why is it easier to demonstrate the wave properties of electrons than protons?
because electrons have less mass, so larger wavelengths
85
New cards
Equation relating wavelength, plank's constant and momentum:
p \= h / wavelength
86
New cards
Kinetic energy \=
1/2mv^2
87
New cards
Equation relating wavelength, plank's constant,
E \= hf
88
New cards
Refractive index equation given speeds
n1 \= (c / c1)
n1 \= refractive index in material 1
c \= speed of light in vacuum
c1 \= speed of light in material 1
89
New cards
A wavelength in radians \=
2pi
90
New cards
The equation for diffraction grating experiments
n * wavelength \= d sinX
d is separation of gaps
x is angle f diffraction
n is the order number
91
New cards
State what is meant by the specific charge of a nucleus and give an
appropriate unit for this quantity.
the ratio of charge to mass of nucleus
C /kg
92
New cards
Nucleus X has the same nucleon number as nucleus Y. The specific charge of
X is 1.25 times greater than that of Y.
Explain, in terms of protons and neutrons, why the specific charge of X
is greater than that of Y.
total number of protons and neutrons the same but more protons therefore greater charge
93
New cards
Describe how the strong nuclear force between two nucleons varies with the separation of the nucleons quoting suitable values for separation.
repulsive then attractive(1)
short range(1)
94
New cards
An unstable nucleus can decay by the emission of an alpha particle.
State the nature of an alpha particle.
a helium nucleus
95
New cards
State what is meant by isotopes.
same atomic number/proton number (1)

different number of neutrons/nucleons (1)
96
New cards
A stable atom contains 28 nucleons.
Write down a possible number of protons, neutrons and electrons contained in the atom.
number of protons \= number of electrons (1)

number of protons + number of neutrons \= 28 (1)
97
New cards
Describe how the strong nuclear force between two nucleons varies with the separation of the nucleons, quoting suitable values for separation.
repulsive below / at 0.5 fm (accept any value less or equal to 1 fm) ✓
attractive up to / at 3 fm (accept any value between 0.5 and 10 fm) ✓
short range OR becomes zero
98
New cards
State the combination of quarks that makes up a neutron.
d + d + u
99
New cards
State the products arising from the decay of an anti-down quark
anti up-quark plus positron plus electron neutrino
100
New cards
Name the class of particles of which the proton is a member.
baryon / hadron