6.4

Question 1

Unified Atomic Mass Unit

Answer 1

1/12 the mass of a carbon-12 atom.

Question 2

Proton number

Answer 2

the number of protons inside the nucleus of a particular atom.

Question 3

Nucleon number

Answer 3

the number of nucleons (protons and neutrons) inside the nucleus of a particular atom.

Question 4

Isotopes

Answer 4

atoms of the same element which contain the same number of protons but varying numbers of neutrons.

Question 5

Alpha particle scattering experiment

Answer 5

1908 Rutherford: Geiger and Marsden
vast majority empty space
most of mass in central nucleus
nucleus small positive charge

Question 6

Strong nuclear force

Answer 6

acts between nucleons and holds the nucleus together against the electrostatic repulsion of protons

Question 7

Nuclear diameter order

Answer 7

10^-14 m

Question 8

How does the strong force vary with distance?

Answer 8

Repulsive force between nucleons for distance of separation up to e. 0.510^15 m
Attractive between distances of 310^-15 and 0.510^-15m
Beyond a separation of 310^-15m the force approaches zero

Question 9

Fundamental particles

Answer 9

Particles that cannot be broken down into smaller components

Question 10

Hadrons

Answer 10

Particles consisting of a combination of quarks to give a net zero or whole number charge (protons and neutrons)

Question 11

Leptons

Answer 11

Electrons and Neutrinos

Question 12

Quarks

Answer 12

Components of Hadrons, have a fractional electric charge. They are the fundamental particles

Question 13

Neutrino

Answer 13

almost no mass, zero charge.

antimatter partner: anti-neutrino

Question 14

Weak nuclear force

Answer 14

Felt by quarks and leptons.
Can change quarks from one type to another.
Can change leptons from one type to another.
Responsible for beta decay

Question 15

Antiparticle

Answer 15

Particle of antimatter that has the same rest mass as its matter counterpart.
When charged has equal and opposite charge to matter counterpart.

Question 16

Alpha particle

Answer 16

Two protons & two neutrons ejected from the nucleus during radioactive decay
Emitted due to high instability

Question 17

Beta particle

Answer 17

High speed electron emitted from the nucleus during beta decay
Produced when a neutron turns into a proton

Question 18

Gamma ray

Answer 18

Form of electromagnetic wave with wavelength between 10^-16 and 10^-9
Emitted during gamma decay

Question 19

Beta-minus decay

Answer 19

Neutron in the nucleus breaks down into a proton under weak nuclear force, and a beta-minus particle and an anti neutrino are emitted
A beta-minus particle is an electron

Question 20

Beta-plus decay

Answer 20

Proton in the nucleus breaks down into a neutron under the influence of the weak nuclear force, and a beta plus particle and a neutrino are emitted.
A beta-plus particle is a positron

Question 21

Activity

Answer 21

The number of nuclear decays (gamma rays emitted) per unit time.
Activity of one decay a second is a becquerel (Bq)

Question 22

Decay constant

Answer 22

The probability that an individual nucleus will decay per unit time.
A/N

Question 23

Half life

Answer 23

The mean time taken for the activity of a source, or number of undecayed nuclei present, to halve.

Question 24

Carbon dating

Answer 24

Technique used to determine the age of organic matter form the relative proportions of carbon-12 and carbon-14 isotopes that it contains.
Half life or carbon 14 used to relate number left to time passed

Question 25

Annihilation

Answer 25

Process in which a particle and its antiparticle interact and their combined mass is converted to energy via E=mc^2

Question 26

Pair production

Answer 26

Process of creating a particle-antiparticle pair from a high energy proton

Question 27

Mass defect

Answer 27

Difference in mass between the mass of a nucleus and the total mass of its separate nucleons

Question 28

Binding energy

Answer 28

Minimum energy required to separate the nucleus into its constituent parts

Question 29

Induced nuclear fission

Answer 29

When a nucleus absorbs slow moving neutrons and the resulting unstable nucleus undergoes a fission reaction to split into two smaller nuclei and a small number of neutrons, releasing energy.

Question 30

Chain reaction

Answer 30

Sequence of nuclear reactions produced when an induced nuclear fission reaction triggers more than one further fission reaction

Question 31

Control rod

Answer 31

Rod that can be lowered into the core of a nuclear reactor, absorb neutrons and slow down the chain reaction.
Made of boron usually

Question 32

Moderator

Answer 32

Substance used in a nuclear reactor which slows down neutrons so that they have a greater chance of being absorbed by the fission reaction’s nuclear fuel.0
Made of graphite usually

Question 33

Binding energy

Answer 33

The energy per nucleon that each holds and can release when the binds between two nucleons is broken

Question 34

Nuclear Fusion process

Answer 34

4 protons react, first in pairs then, to form one helium-4 nucleus, this also supplies 25 MeV of energy and 2 positrons, 2 neutrons and 2 gamma photons

Question 35

Advantages of using fusion for power production

Answer 35

No radioactive waste products are formed by the fusion process
Virtually unlimited supply of raw materials (sea water contains deuterium)