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Protons natural effect on each other is that they

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Protons natural effect on each other is that they

repel each other

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A proton's quark configuration is

Up, Up, Down (uud)

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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

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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

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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

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An atom contains

• a positively charged nucleus composed of protons and neutrons.

• electrons that surround the nucleus

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A nucleon is

a proton or neutron in the nucleus

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Each electron has

a negative charge

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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

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The nucleus is ? times the size of the atom

0.00001 (one ten thousandth)

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The charge of a particle is shown in

Coulombs (C)

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The mass of a particle is measured in

Kilograms (kg)

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An electron has ? compared to a proton

• much less mass

• opposite charge

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A similarity between protons and neutrons is

their almost equal mass

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Neutrons are

uncharged

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An electron has a mass ? times smaller than a proton

2000

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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

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Isotopes are

atoms with the same number of protons and a different number of neutrons

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The total number of protons and neutrons in an atom is called

the nucleon number / mass number

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Each type of nucleus is called

a nuclide

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The specific charge of a charged particle =

charge / mass

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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.

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10^-15 =

femto - fm

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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

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The strong force is (range)

Attractive from 4fm to 0.5fm Closer than 0.5fm it becomes repulsive

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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

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What's the name given to a maximum on a standing wave

An antinode

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For the first harmonic, in terms of length: wavelength =

2 L

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The nth harmonic has length L given by

L = (n/2)wavelength

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Points either side of the rest position in a standing wave are ?(phase)

180 degrees out of phase / antiphase

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Points on the same side of the equilibrium position on a stationary wave are?(phase)

In phase

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A progressive wave is

a wave that moves through the medium

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When two waves meet they

Superpose

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The frequency of the nth harmonic is given by

n * fundamental frequency

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If the frequency of the first harmonic is 20Hz, the third has f =

60Hz

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When labeling standing waves, antinodes are labeled ? and nodes are labeled ?

Antinodes : A

Nodes : N

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Longitudinal waves differ from transverse in that

points on the wave oscillate in line with the direction the wave travels.

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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

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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

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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

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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

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Monochromatic light passes from air into water. The ? change but not the ?

The velocity and wavelength change but not the frequency

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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

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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)

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State the characteristic features of transverse waves

(particle vibration) perpendicular to direction of propagation (or energy transfer) (1)

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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

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Define the amplitude of a wave.

maximum displacement from equilibrium/mean position/mid-point/etc (1)

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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)

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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

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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

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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

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Any process of creating ions is called

ionisation

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?, ? and ? create ions when they pass through atoms

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? 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

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An electron that moves through a potential difference of 2000V is ?eV

2000eV

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An ion of charge +2e moves though a potential difference of 10V is ?eV

20

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Atoms can absorb energy from colliding electrons without being ionized via

excitation

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The energy values at which an atom absorbs energy are its

excitation energies

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The lowest energy of an atom is called its

ground state

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Excitation energy measurements are used to construct

an energy level diagram for the atom

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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

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Acceleration of free fall is

The acceleration of an object acted on only by the force of gravity

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Particles that consist of two protons and two neutrons

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A point on a stationary wave moves

up and down either side of the rest position / equilibrium position

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Two points on a stationary wave, one either side of the rest position, have the phase relationship:

180 degrees out of phase

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Two points on a stationary wave that are the same side of the rest position are

in phase

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Halfway between two nodes is a

antinode

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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

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Stationary waves: Equation to find frequency of nth harmonic

f = (n * c) / 2L

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A guitarist wants to increase the fundamental frequency of his strings, how might he do it?

Increase the tension

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Define: fundamental frequency

the frequency of the first harmonic

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frequency is

the number of full wave cycles per second

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in longitudinal wave, points on the wave

oscillate in the axis of the wave's direction of travel

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Total internal reflection occurs when

the angle of incidence is greater than the critical angle

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equation for a wave passing between two materials, involving their refractive index and angles

n1 * sinANGLE1 = n2 * sinANGLE2

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The critical angle is found using the equation:

n1 * sinANGLEc = n2 * sin90 Where ANGLEc is the critical angle, being reflected 90 degrees

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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 =

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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)

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Work function equation

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Intensity of light is

the number of photons striking a surface per second

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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

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In the work function what is Ek?

The maximum amount of kinetic energy has after escaping an atom

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What kind of experiment would confirm that electrons have wave-like nature?

diffraction (through an atomic lattice)

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why is it easier to demonstrate the wave properties of electrons than protons?

because electrons have less mass, so larger wavelengths

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