# Physics Module 6 - Nuclear and particle physics

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How did Rutherford come to the conclusion that the atom is mainly empty space?
Most of the alpha particles went straight through the foil
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During Rutherfords experiment some alpha particles were deflected through large angles, what does this mean about the atom?
They must have a highly positive chage to repel them. (he names this the nucleus)
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Why did Rutherford conclude the nuclue must be very tiny?
Very few particles were deflected at right angles
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Why must most of the mass be in the nucleus of an atom?
Fast alpha particles were deflected back by the nucleus
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Describe the model of the atom
Positive nuclues containing neutrons and positivelky charged protons. Protons and neutrons are both nucleons. Orbiting the core are electrons with a negative charge
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What is the Proton number of an atom?
the number of protons in the nucleus of an atom
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What is the nucleon number of an atom?
The total number of protons AND neutrons in the nucleus of an atom
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What is an isotope?
Atoms with the same number of protons but differnt numbers of neutrons. Eg, Carbon-12 and Carbon-13
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What are the aprox diameters of an atom and a small nucleus?
Atom - 0.1nm, nucleus - a few fm
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How does the nuclear radius change with nucleon number?
Increases proportionally to the cube root of the nucleon number. (R=r0A^1/3)
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What is the shape a nuclues can be assumed to be?
A sphere and iths volume can be caluculated by V=4/3(pi)^3
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In what range is strong nuclear force repulsive?
<0.5fm
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In what range is stron nuclear force attractive and can hold a nucleus together?
0.5fm< r <3fm
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State the type of particle affected by strong nuclear force
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Name a force through which an electron can interact with other particles?
Weak nuclear force/ gravity/ electrostatic
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What is the relative charge and mass of a neutrino is a hadron or a lepton?
0 mass and 0 charge. Lepton
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How do anti particles differ from corresponding particles?
They have oppostie charge
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How are anti particles the same as thier corresponding particles?
They have the same mass
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What is the electrons anti particle?
positron (+1)
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What is the anti particle for a neutron?
Antineutron (0)
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An antineutrino is the anti particle for what?
Neutrino (0)
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What is the anti particle for a proton?
Antiproton (-1)
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What is the equation used the define the relationship between energy and mass?
E=mc^2
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Describe what is produced in a pair production
energy can be converted into mass and produce particles, if there is enough enegry. The mass is always produced in a particle-anti particle pair.
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What is produced in annaihiliation of a particle and its anti particle?
Two photons
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What is a lepton?
Fundimental particle thats doesnt feel strong nuclear forces
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What are the two types of leptons?
Electrons and Neutrinos
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Particles that can feel strong nuclear forces
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State the names of the three quarks and their anti- quarks in the simple quark model
Quarks- Up (u) Down (d) Strange (s) Anti Quarks- Anti up, Anti down, Anti strange
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State the charges of three anti- quarks in the simple quark model
Up -2/3e, Down 1/3e, Strange 1/3e
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what is the quark composition of a proton and a neutron?
Proton- uud Neutron-udd
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Explain beta minus decay in terms of the quark model
A neutron is changed into a proton. uud changes to udd
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What quantity is conserved in all quark interactions?
Charge
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When an unstable atomic nucleus breaks down to become more stable by releasing energy and particles.
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What type of nuclear radiation consists of 2 protons and 2 neutrons?
Alpha
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What tupe of nuclear reaction is a high frequacy wave?
Gamma
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What type of radiation consists of an electron?
Beta
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What is the decay constant of a radio active material?
The probability of an atomic nucleus decaying per unit time
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What its meant by activity of a radio active material?
The number of atomic nuclei that decay per second
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A student rolls a number of six sided dice, removes those showing six and then rolls again. Why is this used to show radioactive decay?
Rolling a six on a dice is a random event with a constant probability just as radioactive decay is.
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What is the half life of an isotope?
The average time it takes for a number of undecided nuclei to halve
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Describe how you would find an isotopes half life from a graph
Read value of nuclei when t=0, Go to half the original number of unstable on the y-axis. Read from the graph where the corresponding x-value would be
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Give an example of an isotope used in radioactive dating
Carbon
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What is meant by binding energy of a material?
A measure of how strongly the nucleus is held together
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What is nuclear Fission?
When a large nuclei splits in to 2 smaller nuclei. It can be induced by firing neutrons at the nucleus. When the nucleus absorbs the neutrons, it becomes unstable and will undergo fission
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What is nuclear Fusion?
The fusing of two smaller nuclei to form one larger nucleus.
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Why do light nuclei require high temperatures to fuse together?
For fusion to take place temp must be very high so the nuclei can travel fast enough to overcome the repulsion.
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Describe a fusion reaction
when the neutrons released by nuclear fission cause other nuclei to fission and release more neutrons
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why do neutrons need to be slowed down by a moderator in a fusion reaction?
in order for the uranium nuclei to absorb them to induce fission
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how are control rods used to control the rate of reaction in a fission reactor?
they are made of a material that absorbs neutrons. By insetting them into the reactor, the number of reactions can be limited. the rate of reaction can therefore be controlled by changing how far the control rods are inserted into the reactor
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What properties does the materials used for a coolant in a fission reactor need to have?
the material used for a coolant needs to be a liquid or gas at room temperature so it can be pumped around the reactor. it also needs to be efficient at transferring heat fro, the reactor.
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How can nuclear waste impact the environment?
facilities must be deep underground permanently changing the landscape, leaked waste can contaminate water supplies and damage environment
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## Other cards in this set

### Card 2

#### Front

During Rutherfords experiment some alpha particles were deflected through large angles, what does this mean about the atom?

#### Back

They must have a highly positive chage to repel them. (he names this the nucleus)

### Card 3

#### Front

Why did Rutherford conclude the nuclue must be very tiny?

### Card 4

#### Front

Why must most of the mass be in the nucleus of an atom?

### Card 5

#### Front

Describe the model of the atom