Nuclear Physics

Question 1

3 isotopes of hydrogen

Answer 1

(1 1) Protium
(1 2) Deuterium
(1e 3) Tritium

Question 2

Fissile material

Answer 2

Material that can undergo the fission reaction

Question 3

The Rutherford model

Answer 3

A gold leaf experiment conducted in 1909 by Hans Geiger and Ernest Marsden in which alpha particles were fired at a thin gold leaf (1000 atoms thick). About 1/8000 particles hit the very small, surrounded mostly by empty space, nucleus(containing most of the mass) and were deflected due to the like charge of the alpha particles and protons in the nucleus.

The atoms far away would be unaffected by the forces and continue in a straight path, those closer would be deflected, and closer would completely turn around

Question 4

Atom

Answer 4

Smallest unit of matter that still retains the chemical properties of its elements

Question 5

Structure of an atom

Answer 5

Consists of a central, positive nucleus containing protons and neutrons, orbited by shells/orbitals carrying negative electrons.

Question 6

What is this referred to as
A=
X=
Z=

Answer 6

Nucleic notation
A = (big no.) atomic mass/nucleon no.
X= element symbol
Z= proton/atomic mass

Question 7

Isotopes

Answer 7

Atoms with the same number of protons but different mass numbers. Most radioactive elements exist as isotopes

Question 8

What happens during nuclear processes

Answer 8

The proton and atomic mass number are conserved
The H represents an alpha particle and nuclear radiation

Question 9

What prevents electrons from falling into the nucleus

Answer 9

Their speed

Question 10

Proton number

Answer 10

Number of protons in a nucleus

Question 11

Proton charge

Answer 11

1.6x10*-19

Question 12

Nucleon number

Answer 12

Number of protons and neutrons in an atomic nucleus

Question 13

Isotope

Answer 13

Same proton number different mass number

Question 14

Nuclide

Answer 14

Species of nucleus having particular values of proton and nucleon numbet

Question 15

2 isotopes of helium

Answer 15

3/2 -rare
4/2 - commonest

Question 16

What does it mean when an isotope is unstable

Answer 16

It undergoes radioactive decay, emitting radiation as it changes from one element to another

Question 17

Nuclear fission

Answer 17

When a heavier nucleus divides into 2 smaller ones. Induced by an introduction of a neutron as the neutron has no charge and is not deflected by the positively charged protons in the nucleus.

Question 18

Radioactive decay

Answer 18

The decay of a radioactive substance when its atomic nuclei emit radiation (to become stable?)

Question 19

Nuclear fusion

Answer 19

The process by which energy is released by joining together 2 small light nuclei to form a new heavier nucleus
In the sun: (When 2 energetic hydrogen atoms collide and fuse to form a helium atom)

Question 20

Contaminated

Answer 20

When an object has acquired some unwanted radioactive substance

Question 21

Irritated

Answer 21

When an object has been exposed to radiation

Question 22

Background radiation

Answer 22

Radiation from the environment which we are exposed to all the time

Question 23

Sources that make a significant contribution to background radiation (4)

Answer 23

Radon gas (and thoron) in air (main)
Cosmic rays
Food and drink
Rocks and buildings

Question 24

How can ionising nuclear radiation be measured

Answer 24

With a detector connected to a counter (geigercounter)

Question 25

Sources of artificial radiation (3)

Answer 25

Medical Fallout from weapons test Air travel, TV sets

Question 26

Describe the emission of radiation from a nucleus

Answer 26

Spontaneous and random in direction

Question 27

What does an atom of a radioactive substance emit

Answer 27

Either an alpha or beta particle Emits energy in the form of a gamma ray (sometimes same time,sometimes later)

Question 28

How fast gamma rays travel

Answer 28

At the speed of light

Question 29

Alpha nature

Answer 29

Alpha radiation has a high power of ionisation but low penetration

Question 30

Ionisation

Answer 30

When a particle becomes radioactively charged by losing/gaining electrons

Question 31

Ionising radiation

Answer 31

Radiation that causes ionisation

Question 32

High ionising, low pentrating

Answer 32

Alpha (sheet of tissue paper)

Question 33

Low ionising high penetrating (aluminium stops it)

Answer 33

Gamma

Question 34

Low ionising, high penetration (lead needed to stop it_

Answer 34

Gamma rays

Question 35

Penetrating power

Answer 35

How far radiation can penetrate into different materials

Question 36

deflection of α-particles, β-particles and γ-radiation in magnetic fields

Answer 36

Alpha deflected Beta deflected more in the opposite direction Gamma not deflected

Question 37

deflection of α-particles, β-particles and γ-radiation in electric fields

Answer 37

Alpha is positively charged Beta is negatively charged Gamma is neutral

Question 38

Effects of ionising nuclear radiations

Answer 38

Death in cell due to ionisation Damage to nucleus results in control mechanisms being broken down and uncontrollable division (tumor + cancer) Damage DNA if affected cell is a gamete, mutation passed through generations as the egg may not develop at all, or form a genetic disorder

Question 39

Why may isotopes of an element be radioactive

Answer 39

Due to an excess of neutrons in the nucleus an/or the nucleus being too heavy

Question 40

Radioactive decay

Answer 40

Change in an unstable nucleus that can result in the spontaneous and random emission of alpha/beta particles or gamma rays.

Question 41

What happens to the nucleus during alpha or beta decay

Answer 41

It changes to that of a different element

Question 42

Half life

Answer 42

Time taken for half the nuclei of the isotope to decay

Question 43

Radioactive tracing

Answer 43

Technique that uses a radioactive substance to trace the flow of liquid or gas/ to find the position of cancerous tissue in the body

Question 44

effect of α-decay, β-decay and γ-emissions on the nucleus

Answer 44

Increase in stability and reduction in the amount of excess neutrons Neutron -> proton + electron

Question 45

Beta decay

Answer 45

Decay of a radioactive nucleus by emission of a beta-particle (used in carbon dating)

Question 46

how radioactive materials are moved, used and stored in a safe way

Answer 46

Reduce exposure time Increase distance between source and living tissue Use shield to absorb radiation Gloves and tongs Stored in a container that absorbs as much radiation as possible

Question 47

Uses of radioactivity (5)

Answer 47

Thickness control - beta radiation (gm tubes) Medical (diagnosing and treating cancer and X-rays) - gamma rays IODINE 123 House hold fire alarms - alpha (knows when alpha is being blocked by smoke) Irritating food to kill bacteria (gamma) Sterilisation of equipment - gamma rays