Particles & Nuclear Physics

Question 1

Proton number (or atomic number)

Answer 1

The number of protons in the nucleus of an atom

Question 2

Neutron number

Answer 2

The number of neutrons in the nucleus of an atom

Question 3

Nucleon number (or mass number)

Answer 3

The number of protons and neutrons in the nucleus of an atom

Question 4

Plum Pudding model

Answer 4

A model of the atom in which negative charges are distributed throughout a sphere of positive charge

Question 5

Isotope

Answer 5

An atom with the same number of protons in the nucleus but a different number of neutrons

Question 6

Conservation of ___

Answer 6

The total ___ before a nuclear change will equal the total ___ after.

Question 7

Quantities conserved in nuclear decay

Answer 7

Nucleon number, mass-energy, lepton number, baryon number, charge

Question 8

Atomic mass unit

Answer 8

A 1/12th the mass of a C-12 nucleus

Question 9

Thermal neutron

Answer 9

These are slow-moving neutrons

Question 10

Control rods

Answer 10

Rods of a neutron-absorbing material used to reduce the rate of a nuclear chain reaction

Question 11

Coolant

Answer 11

A substance used to transfer thermal energy from the core of a nuclear reactor

Question 12

Induced nuclear fission

Answer 12

A fission reaction started when a neutron is absorbed by a nucleus

Question 13

Mass defect

Answer 13

The difference between the total mass of the individual, separate nucleons and the mass of the nucleus

Question 14

Moderator

Answer 14

A material used in a nuclear reactor to slow down fast-moving neutrons so that they have a greater change of interacting with the fissile nuclei

Question 15

Activity

Answer 15

The rate of decay or disintegration of nuclei in a radioactive sample

Question 16

Decay constant

Answer 16

The probability of a nucleus decaying per unit time

Question 17

N as in A = λN

Answer 17

The number of undecayed nuclei in a sample

Question 18

Half-life

Answer 18

The mean time taken for half the number of active nuclei in a radioactive sample to decay

Question 19

Chain reaction

Answer 19

An exponential growth of a fission reaction caused by the increasing flux of neutrons causing fission

Question 20

Spontaneous

Answer 20

Occurs without external influence

Question 21

Random

Answer 21

Cannot be predicted

Question 22

Binding energy

Answer 22

The minimum external energy required (per nucleon) to separate all the protons and neutrons in a nucleus

Question 23

Binding energy per nucleon

Answer 23

The minimum external energy required (per nucleon) to separate all the protons and neutrons in a nucleus

Question 24

Antimatter

Answer 24

Particles with the same mass but opposite charge and properties

Question 25

Annihilation

Answer 25

When matter and antimatter collide to produce gamma ray photons only

Question 26

Electro-magnetic intensity

Answer 26

Electromagnetic power per unit cross-sectional area

Question 27

Photon

Answer 27

A quantum of electromagnetic energy