8) Radioactivity

Question 1

What is the mass and charge of a proton?

Answer 1

Mass: 1
Charge: 1

Question 2

What is the mass and charge of a neutron?

Answer 2

Mass: 1
Charge: 0

Question 3

What is the mass and charge of an electron?

Answer 3

Mass: 0.0005
Charge: -1

Question 4

What is the atomic number?

Answer 4

Number of protons

Question 5

What is the mass number?

Answer 5

Number of protons + neutrons

Question 6

What is an isotope?

Answer 6

Atoms of the same element, that contain equal numbers of protons, but different numbers of neutrons in their nuclei

Question 7

What is an alpha particle made of?

Answer 7

A helium nucleus (2 protons, 2 neutrons)

Question 8

What is a beta particle made of?

Answer 8

A fast moving electron

Question 9

What is a gamma ray made of?

Answer 9

A high energy electromagnetic wave

Question 10

Which radioactive particle is the most ionising?

Answer 10

Alpha

Question 11

Which radioactive particle is the least ionising?

Answer 11

Gamma

Question 12

Which radioactive particle has the highest penetrating power?

Answer 12

Gamma

Question 13

Which radioactive particle has the least penetrating power?

Answer 13

Alpha

Question 14

Which radioactive particle is stopped by a few cm air or a few mm or paper?

Answer 14

Alpha

Question 15

Which radioactive particle is stopped by a few cm of aluminium?

Answer 15

Beta

Question 16

Which radioactive particle is slowed down by concrete or a few cm of lead?

Answer 16

Gamma

Question 17

What is ionisation?

Answer 17

When an electron is knocked off an atom and it is turned into an ion

Question 18

Why are alpha particles the most ionising?

Answer 18

Because alpha particles are the most massive they are the most likely to ionise an atom. However, as a result they give up their energy quickly and thus aren’t able to travel very far.

Question 19

Where can background radiation be found?

Answer 19

Everywhere

Question 20

What are some examples of background radiation?

Answer 20

Radon gas, food, cosmic rays (from the sun), many rocks (eg. uranium)

Question 21

What is a danger of ionisation?

Answer 21

Ionisation can cause damage and mutate the cells, this then again can result in cancer

Question 22

What are some measures to reduce exposure?

Answer 22

Stay as far away from the source, spend as little time near the source, shield themselves with lead or concrete.

Question 23

What is a use of radioactive materials?

Answer 23

Generating electricity, tracers for medical + underground water pipes.

Question 24

What are doses of radiation measured in?

Answer 24

Sieverts (Sv)

Question 25

Doses of 4000mSv (4Sv) are likely to be ______

Answer 25

fatal

Question 26

Low doses of under __mSv are very unlikely to cause us harm

Answer 26

10mSv

Question 27

Doses of ____mSv (_Sv) is unlikely to kill someone, but likely to make them feel unwell.

Answer 27

1000mSv (1Sv)

Question 28

1Sv = ____mSv

Answer 28

1Sv = 1000mSv

Question 29

Radioactive decay is a _____ process

Answer 29

random

Question 30

What is a half-life?

Answer 30

The period of time taken for half the number of atoms to decay

Question 31

What is nuclear fission?

Answer 31

When a large atomic nucleus (eg. Uranium) splits into two smaller nuclei

Question 32

Which isotope of Uranium is used in generating electricity?

Answer 32

Uranium-235 (later uranium 236)

Question 33

What does the term 'fissile' mean?

Answer 33

Capable of splitting

Question 34

What happens during nuclear fission?

Answer 34

A neutron is fired at a Uranium-235 nuclei, turning it into a Uranium-236 nuclei, enabling it to split into two daughter nuclei and 3 single neutrons. These neutrons will travel and hit other uranium-235 nucleus continuously starting a new reaction. This is why this is called a 'chain reaction'.

Question 35

What does the graphite moderator do?

Answer 35

It slows down the Neutrons for them to hit other Uranium-235 nuclei.

Question 36

What do the control rods do?

Answer 36

Absorb nuclei, slowing down or stopping the reaction

Question 37

What material are control rods made of?

Answer 37

Boron

Question 38

What happens to the temperature inside the nuclear reactor when the control rods are lowered?

Answer 38

Temperature will be lower because more neutrons are absorbed by the control rods, meaning less uranium-235 nuclei are hit.

Question 39

What is nuclear fusion?

Answer 39

Small nuclei are combined to produce large nuclei.

Question 40

What type of radiation is released during Nuclear Fusion?

Answer 40

Gamma

Question 41

What are some of the conditions which are required for nuclear fusion to occur?

Answer 41

High temperatures + pressure