P7 - Radioactivity 1️⃣✅

Question 1

What is activity in terms of radioactivity?

Answer 1

The rate of decay/ number of unstable atoms that decay per second in a radioactive source

Question 2

What is alpha radiation?

Answer 2

Alpha particles, each composed of 2 protons and neutrons, emitted by unstable nuclei

Question 3

What is an atomic number?

Answer 3

The number of protons (which equals the number of electrons) in an atom.q

Question 4

What is beta radiation?

Answer 4

Beta particles that are high energy electrons created in, and emitted from unstable nuclei

Question 5

What is count rate?

Answer 5

The number of counts per second detected by a Geiger counter

Question 6

What is gamma radiation?

Answer 6

Electromagnetic radiation emitted from unstable nuclei in radioactive substances

Question 7

What is half-life?

Answer 7

The average time taken for the count rate to fall to half its original value

Question 8

What is the unit of radioactivity?

Answer 8

Bequerel, Bq

Question 9

What is an alpha particle?

Answer 9

A particle that consists of 2 protons and neutrons

Question 10

What is a beta particle?

Answer 10

A particle that consists of high speed electrons

Question 11

What is gamma decay?

Answer 11

The emission of electromagnetic radiation from an unstable nucleus

Question 12

What is the charge of alpha?

Answer 12

+2

Question 13

What is the charge of beta?

Answer 13

-1

Question 14

What is the charge of gamma?

Answer 14

0

Question 15

What is alphas symbol/equation for decay?

Answer 15

A (A - 4) 4
X → Y + α
B (B - 2) 2

Question 16

What is betas symbol/equation for decay?

Answer 16

A A 0
X → Y + β
B (B + 1) -1

Question 17

What is gammas symbol/equation for decay?

Answer 17

A A 0
X → Y + γ
B B 0

Question 18

What type of radiation is most dangerous inside the body?

Answer 18

Alpha

Question 19

What type of radiation is most dangerous outside the body?

Answer 19

Beta

Question 20

What type of radiation is most dangerous at a distance?

Answer 20

Gamma

Question 21

What is alphas ionising power?

Answer 21

Alpha has the highest ionising power

Question 22

What is betas ionising power?

Answer 22

Beta has a high ionising power

Question 23

What is gammas ionising power?

Answer 23

Gamma has a low ionising power

Question 24

How far does alpha travel in air?

Answer 24

Alpha travels as few centimetres in air

Question 25

How far does beta travel in air?

Answer 25

Beta travels around 1m in air

Question 26

How far does gamma travel in air?

Answer 26

Gamma has a virtually unlimited range in air

Question 27

What is alpha stopped by?

Answer 27

Alpha is stopped by a sheet of paper & cant get through skin

Question 28

What is beta stopped by?

Answer 28

Beta is stopped by a few millimetres of aluminium and a thin sheet of lead

Question 29

What is gamma stopped by?

Answer 29

Gamma is stopped by several millimetres of thick lead or meters of concrete

Question 30

What is irradiation?

Answer 30

Irradiation is when an object is exposed to nuclear radiation

Question 31

What is contamination?

Answer 31

Contamination is when atoms of a radioactive materials are on or in an object

Question 32

How can you stop irradiation?

Answer 32

Irradiation is prevented by shielding, removing, or moving away from the source of radiation

Question 33

How can you stop contamination?

Answer 33

Contamination can be very difficult to remove

Question 34

What is background radiation?

Answer 34

Radiation that is around us all the time

Question 35

What is nuclear fission?

Answer 35

Nuclear fission is when a large unstable nucleus absorbs an extra neutron and splits into 2 smaller nuclei of roughly equal size

Question 36

What happens during nuclear fission?

Answer 36

The splitting of large and unstable nuclei into 2 smaller nuclei

Question 37

What is nuclear fusion?

Answer 37

Nuclear fusion is when two light nuclei join to make a heavier one. Some of the mass is converted to energy and transferred as radiation (only happens in stars)

Question 38

What is an isotope?

Answer 38

An isotope is an atom of the same element with different numbers of neutrons

Question 39

What is radioactivity?

Answer 39

Radioactivity is when particles are unstable and they give out energy from their nucleus to become more stable

Question 40

What is ionisation?

Answer 40

Ionisation is removing an electron from an atom

Question 41

What is radiotherapy?

Answer 41

The use of radioactivity to treat diseases like cancer

Question 42

How can radiation be used in medical means?

Answer 42

Gamma-emitting tracers are injected or swallowed by a patient, allowing for gamma cameras to create an image showing where the tracer has gone. The half-life of the tracer MUST be short enough so that it will decay shortly after the image is produced to limit the patients radiation dose

Question 43

Does nuclear fission occur naturally?

Answer 43

No, for it to hapen on its own is very rare so in order for humans to use the energy it generates we have to fire a neutron at the nuclei in order for it to absorb it and split into 2 smaller nuclei

Question 44

What is meant by a chain reaction in nuclear fission?

Answer 44

That as the 1st nuclei splits into 2 smaller nuclei via the neutron being absorbed those 2 nuclei also absorb a neutron, casuing 2 more to be released from each of the previous nuclei forming a chain reaction

Question 45

How does a nuclear bomb work?

Answer 45

An uncontrollable chain reaction that releases huge ammounts of energy

Question 46

How do nuclear reactors not also explode due to chain reactions like nuclear bombs?

Answer 46

They are conrolled using control rods to remove some of the neutrons so that the chain reaction happens much slower and is controlled to control the ammount of energy that is released