Hulk it

Question 1

What is ionising radiation?

Answer 1

These are fast moving particles that collide with orbital electrons, ejecting them out of the orbital leaving behind a positively charged nucleus and negative electron, these are positive and negative ions.

Question 2

What are the types of ionising radiation?

Answer 2

• Alpha particles are the nuclei of Helium atoms
• Beta particles have the mass of an electron where Beta plus (positron) is positively charged and Beta minus (electron) is negatively charged
• Gamma rays are photons with no mass or charge travelling at the speed of light

Question 3

How is nuclear stability achieved?

Draw visual

Answer 3

Within the nucleus there are protons that repel each other, and tend to break up the nucleus, to overcome this, the nucleus contains neutrons that bind with each other and the protons.

Question 4

Differences between smaller and larger nuclei in terms of nucleotides

Answer 4

Small Nuclei have equal numbers of protons and neutrons to maintain stability
Large Nuclei have more neutrons than protons to maintain stability, this is why larger nuclei tend to be more unstable

Question 5

Draw a segre plot

Answer 5

g

Question 6

What are the different models of the atom?

Answer 6

• Thompson pudding
  Rutherford Planetory
  Bohr (Rutherford/bohr) - energy levels

Question 7

Nuclear decay is..

Answer 7

random and spontaneous

Question 8

Radioactive decay and its effect on mass

Answer 8

decay is not reducing mass but radioactive mass, the mass will not reduce eg. uranium becomes half lead

Question 9

What is the attractive force (strong force) and is it present in the nucleus?

Answer 9

This is the force of attraction between the neutrons and protons, it acts over an extremely short range of 1 x 10^-15, this force is not present outisde the nucleus.

As distance increases, strong nuclear force decreases

Question 10

What is the electromagnetic force, what is it inversely proportional to?

Answer 10

this is the repulsive force between protons and the attractive force between protons and electrons. It acts over a very large range and is inversely proportioal to distance squared. This electromagnetic force has a magnitude of 1/100 of the strong force

Question 11

What is the weak nuclear force?

Answer 11

this is the force between the departing Beta particle and the daughter nucleus. It acts over a range of 1 x 10^-18m and has a strength of 1 x 10^-13

Question 12

Why does alpha decay occur?

Answer 12

A nucleus with too many protons and neutrons breaks up emmitting alpha particles which are nuclei of helium atoms

Question 13

Do alpha particles undergo many collisions, and why can they not penetrate deep into matter

Answer 13

Alpha particles are large and undergo many collisons as they pass through matter producing many ions. With each collision the alpha particle looses energy due to the large number of collisions it looses its energy quickly and comes to an abbrupt halt. Therefore, the alpha particle cannot penetrate deep into matter.

A thin sheet of paper or the top layer of human skin can absorb the alpha particles. Therefore, alpha particles are not a danger as an external source.

Question 14

What occurs in beta plus decay?

Answer 14

Occurs in nuclei which contain too many protons or too many neutrons. A proton in the nucleus breaking up into a neutron and a beta plus particle - known as a position

Question 15

What occurs in beta minus decay

Answer 15

This is the process of a neutron breaking up into a neutron and a beta minus particle

Question 16

Why can beta particles penetrate further into matter?

Answer 16

Beta particles are much smaller than alpha particles, they undergo less collisons as they pass through matter and produce less ions. Therefore, they can penetrate further into matter, for example, a beta particle can penetrate 2m in air, 7cm in plastic and 1mm in lead

Question 17

Momentum conservation during beta decay

Answer 17

During beta decay the parent nucleus is at rest with 0 momentum. After the decay, the daughter nucleus is at rest with 0 momentum, while the beta particle is in motion with some momentum. For momentum conservation to be valid, the total initial and total final momentum have to be 0, thus after the decay the momentum of the beta particle needs to be cancelled by the momentum of another particle, this particle is known as the neutrino, which has a near 0 mass and moves at a speed close to that of light, in an opposite direction to the beta particle.

Question 18

where is the anti-neutreno found

Answer 18

beta minus decay

Question 19

what happens when you rip a neutron out of a radioactive material?

Answer 19

a proton, electron and anti-neutrino come out

Question 20

Draw beta plus and beta minus on a space time graph

Answer 20

diagram

Question 21

Note- what happens in non-quantum measurements (beta decay)

Answer 21

• all these events occur simultaneously

- the ejected particles do not necessarily come from the same place

Question 22

how does gamma radiation occur?

draw diagram

Answer 22

This is associated with alpha decay and gamma decay where the daughter nucleus is produced in an excited state.
When the daughter nucleus releases the excitation energy in the form of gamma radiation
.

Question 23

why is gamma radiation highly penetrating?

Answer 23

Gamma radiation consists of gamma photons that have negligable mass but move at the speed of light, carrying momentum and energy. Gamma radiation interacts very little with matter producing very few ions, therefore highly penetrating. Gamma radiation can penetrate 2m of lead.

Question 24

1st law of radioactive decay:

Activity: this is the number of nuclei decaying per second

Answer 24

A proportional to N
A= wavelength (decay constant)N
units of A =Bq (Becquerat)
1Bq= 1dps (disintegrations per second)

Question 25

Law 2 : Exponential decay law

Answer 25

N= No e ^-wavelength x t
or
A =Ao e ^-wavelength x t

Question 26

3. Half - ;life

Answer 26

Time taken for half the nuclei to decay.

T 1/2 = 0.693/ wavelength

Question 27

Simplified decay law- how nuclei decay as a fraction of No

Answer 27

N=1/2^n x No

Question 28

What does a gamma ray emit?

Answer 28

A photon - highly energised, very short wavelength, very high frequency
A gamma ray is a highly energetic, very short wavelength (energy)- smaller than an atom

Question 29

All 3 forms of ionising radiation releases particles ie. evidence of decay is the ejected particles

Answer 29

Alpha/beta decay all release daughter nucleides - mass

but gamma releases a photon (energy with no mass)

Question 30

Radiation capability

Answer 30

The ability to ionise/penetrate

Question 31

Penetrating capability

Answer 31

Gamma- 2 protons, 2 neutrons
Beta- ejecting a positron/electron and neutrino and antineutrino
Alpha- whole proton, 2 x smaller than beta

Question 32

draw magnetic field diagram

Answer 32

d

Question 33

carbon 14 dating

Answer 33

love

Question 34

What was einsteins problem

Answer 34

the mass of a proton +neutron is not the same as a neutron and proton parts
The parts of the nucleus weigh less than the parts

Question 35

Mass defect formula

Answer 35

Mass defect- nucleus
Change in E = mc^2
M proportional to E
speed of light will not change
if the mass disappeared there must be a relationship with energy

Question 36

what did Einstein propose the mass defect was?

Answer 36

E proposed that this was not a defect, but the energy needed to bind a nucleus together
mass nucleus = mass of components + binding energy

Question 37

Steps to find energy

Answer 37

1. Find A and Z
2. Find A-Z
3. find the mass of all the separate parts
4. Compare 3 with A
5. this is the binding energy

Question 38

Mass defect formula

Answer 38

Change in mass = Nmn +Zmp+ Zme - Matom

This difference in mass is stored as energy in the bonds that holds the nucleus together, this mass energy conversion is based on einsteins equation E=mc^2

Question 39

BE is E in E=mc ^2

Answer 39

This is the energy equivalent of the mass defect that is sotred in the bonds between neutrons and neutrons and protons

Question 40

How much is 1 amu

Answer 40

1u= 1/12 the mass of carbon

Question 41

how many eV is 1 mega ev

Answer 41

1MeV = 10^6 eV

Question 42

Variation of binding energy

Answer 42

The large atoms had a large amount of binding energy per nucleon while the small atoms had a low amount of binding energy per nucleon.
Therefore, the large atoms could be split up to release a large amount of energy which is known as fision while the small atoms can be made to combine to form a smaller atom and release the excess binding energy which is known as fusion.
Iron-56 has the highest amount of binding energy per nucleon indicating its strength
Nickel also sits next to iron - both are very hard

Question 43

What is fision?

Answer 43

This is the process of releasing energy by splitting up a large nucleus by impacting it with a fast moving light particle, the light particle destabalizes the nucleus and breaks it up into smaller nuclei, in the process releases fast moving particles that carry away the fision energy.