Radiation (2)

Question 1

What does an atom consist of?

Answer 1

It consists of positive protons and neutrons (which contain no charge) and negative electrons which orbit the atom.

Question 2

What is there more of as an atom gets bigger?

Answer 2

As an atom gets bigger there are more protons, neutrons and electrons.

Question 3

Why are most atoms electrically neutral?

Answer 3

Because they have an equal number of positive protons and negative electrons.

Question 4

Why are small atoms stable?

Answer 4

They are stable because they have a fairly similar number of protons and neutrons.

Question 5

What very big atoms are unstable and for what reason?

Answer 5

Uranium (92 protons 146 neutrons large imbalance) throws off 3 types of nuclear radiation to become more stable with those 3 types being alpha, beta and gamma.

Question 6

Why is nuclear radiation called that way?

Answer 6

It is called nuclear as it comes from the nucleus.

Question 7

What is alpha radiation?

Answer 7

It’s 2 protons and 2 neutrons meaning it is a Helium nucleus.

Question 8

What is Beta radiation?

Answer 8

It is a fast moving electron.

Question 9

What is gamma radiation?

Answer 9

It is an electromagnetic wave.

Question 10

Where does a Beta particle come from if there are no electrons in a nucleus?

Answer 10

A neutron turns into a proton and an electron which is released as a beta particle.

Question 11

What is it called when a nucleus has emitted a piece of radiation?

Answer 11

It has decayed.

Question 12

At what time might gamma emission occur?

Answer 12

Alongside alpha and beta emission.

Question 13

What is a material containing radioactive atoms called?

Answer 13

Source.

Question 14

If an atom loses or gains electrons what do we say it becomes?

Answer 14

A charged ion, this process is called ionisation.

Question 15

What can ionisation be caused by?

Answer 15

Nuclear radiation.

Question 16

What are alpha, beta and gamma particles called?

Answer 16

Ionising radiations as they can ionise atom which they come close to or collide with.

Question 17

What particle causes the most ionisation and why?

Answer 17

Alpha as they are the biggest of the 3 nuclear radiations. It also has a positive charge meaning it can attract the electrons off an atom. Meaning it causes more ionisation than beta or gamma.

Question 18

What are the different types of radiation stopped by?

Answer 18

Alpha- few cm of air or a shin sheet of paper
Beta- few cm of air or a thin sheet of aluminium
Gamma- thick block of lead

Question 19

What can be used to detect radiation?

Answer 19

Geiger-muller tube or by photographic film as the radiation turns it black.

Question 20

As radiation can kill cells what can it be used for besides radiotherapy?

Answer 20

Sterilising medical equipment and even sterilising food to prolong shelf life.

Question 21

Where is alpha radiation commonly used?

Answer 21

Smoke detectors.

Question 22

What is beta radiation used for in industry?

Answer 22

It can be used to judge the thickness of paper or foil. Tracers can also be used to study the flow of water in pipes.

Question 23

A

Answer 23

A

Question 24

How is the age of artifacts found?

Answer 24

Using carbon dating which involves the process of measuring amounts of carbon 14.

Question 25

What can be used to measure background radiation?

Answer 25

It can be measured by a Geiger-Muller tube and a counter.

Question 26

What must you take into account when measuring how radioactive a source is?

Answer 26

The background radiation.

Question 27

What does the activity of a radioactive source tell us?

Answer 27

It tells us the number of decays happening in a second which is measured in becquerels (Bq).

Question 28

What is the absorbed dose?

Answer 28

It tells you how much radioactive energy 1kg of body tissue absorbs, measured in Grays (Gy).

Question 29

What is the Equivalent Dose (H)?

Answer 29

It is a term which tells you the biological effect that radiation has on the body.

Question 30

How does the Equivalent Dose work?

Answer 30

It takes into account the absorbed dose and the type of radiation absorbed.

Question 31

What is the unit used to measure Equivalent Dose?

Answer 31

Sieverts (Sv).

Question 32

How do you work out the type of radiation in Equivalent Dose?

Answer 32

You take the absorbed radiation and multiply it by a weighting factor (w) as each type of radiation causes a different amount of ionisation so has a different weighing factor.

Question 33

What are the steps you can take to avoid exposure to radiation?

Answer 33

Shielding the source with an appropriate absorber (lead), limiting the time of exposure and putting a big distance between you and the source.

Question 34

What are the steps you should take if you are going to handle a radioactive source?

Answer 34

Using forceps or tongs, never bringing the source close to your eyes, storing in a lead lined box, always washing your hands after handling a source.

Question 35

What happens to a source with time?

Answer 35

It decays and becomes stable meaning the activity of all sources is decreasing.

Question 36

What is the half life?

Answer 36

The time it takes for the activity of a source to fall to half its previous value. (The time taken for half of the radioactive nuclei to decay).

Question 37

What is fractional activity?

Answer 37

It is the term used to describe what fraction of activity the source still has.

Question 38

What is nuclear fission?

Answer 38

It is when a neutron is fired at a large unstable uranium nucleus.

Question 39

How does nuclear fission occur after it is triggered?

Answer 39

The uranium nucleus absorbs the neutron and splits into 2 smaller nuclei. When the nucleus splits some neutrons are emitted. More importantly though the mass of the particles after the reaction is smaller meaning the lost mass can then be turned into heat energy.

Question 40

What are the daughter products?

Answer 40

They are Tellurium and Zircoium and fission products (very radioactive).

Question 41

What is a chain reaction in nuclear fission?

Answer 41

It is when an initial fission reaction is started the nuclei split and release neutrons which then trigger other nuclei starting a chain reaction and releasing a lot of heat very quickly.

Question 42

What is nuclear fusion?

Answer 42

In a fusion reaction 2 smaller nuclei join or fuse together to produce a larger nuclei which causes a neutron and heat to be released (just as it is in fission it is due to lost mass).

Question 43

How is energy generated at a nuclear power station?

Answer 43

Coolant is pumped through the very hot reactor which absorbs the heat and passes near the pipes containing cold water, the cold water absorbs the heat energy and is converted to superheated steam, the steam is then fired out of a nozzle which turns a turbine that is connected to a magnet which sits inside a coil of wires meaning when it is spun it generates electric current in the coil.

Question 44

How much (at present) of the energy in Scotland is being produced by nuclear energy?

Answer 44

30%

Question 45

What equation can be used to calculate the lost mass from the fission and fusion reactions?

Answer 45

E=mc^2 (m= lost mass, c= speed of light)

Question 46

What are the advantages of nuclear fission power?

Answer 46

No greenhouse gasses, very reliable supply of electricity, small amount of fuel creates a lot of electricity.

Question 47

What are the disadvantages of nuclear fission?

Answer 47

Produces waste which is dangerous for thousands of years, storage of such waste is difficult, catastrophic failures may result in a lot of radiation being released, they are very expensive to build and decommission.

Question 48

What are the advantages of nuclear fusion compared to fission?

Answer 48

Fusion reaction does not produce any greenhouse gases or radioactive waste, the fuel is a type of hydrogen found in sea water.

Question 49

What are the disadvantages of fusion compared to fission?

Answer 49

The fusion requires temperatures similar to the core of the sun which is very hard to do and is very expensive. Meaning if we can get fusion working at a lower temperature we can have a clean cheap and renewable energy source.