Nuclear Decay and Energy Flashcards
What is a radioactive element?
Radioactive elements are unstable elements which are made up of atoms with unstable nuclei that are emitting ionising radiation by spontaneous disintegration in aims of attaining a stable form
What is nuclear decay?
Nuclear decay is the inevitable decay of an element to form a stable element, as the nucleus of the decaying atom changes during the dexay
What is true about radioactive emission?
It is spontaneous and random
Where is radioactive radiation emitted from?
The nucleus of the atom
What are the 3 types of radiation?
Alpha α
Beta β
Gamma Υ
What is alpha radiation?
An alpha particle is a fast moving helium nucleus
What is the mass of an alpha particle?
4u
What is the charge of an alpha particle?
2+
What is the range and penetration of an alpha particle?
Short range, stopped by 2cm of air
What is the ionisation of an alpha particle?
High, an alpha particle is strongly ionising
What is the speed of an alpha particle?
An alpha particle is fast moving
Do alpha particles get deflected by electric or magnetic fields?
Yes, alpha particles are weakly deflected by E and B fields
What is a beta particle?
A high energy electron
What is the mass of a beta particle?
1/2000u
What is the charge of a beta particle?
-1
What is the range and penetration of a beta particle?
Medium range, stopped by 2-3mm of aluminium
What is the ionisation of beta particle?
Medium, a beta particle is moderately ionising
What is the speed of a beta particle?
A beta particle moves just less than the speed of light
Do beta particles get deflected by electric or magnetic fields?
Yes, beta particles are strongly deflected by E & B fields because of their low mass
What is a gamma particle?
High energy photon γ
What is the mass of a gamma particle?
Gamma particles are massless
What is the charge of a gamma particle?
Gamma particles have no charge
What is the range and penetration of a gamma particle?
Long range, stopped by 2-3cm of lead
What is the ionisation of a gamma particle?
A gamma particle is weakly ionising
What is the speed of a gamma particle?
A gamma particle moves at the speed of light
Do gamma particles get deflected by electric and magnetic fields?
No
What is half life?
The time taken for the activity of a radioactive substance to decay by half
The activity (A) is proportional to?
The number of radioactive nuclei (N)
What is the equation of activity and number of radioactive nuclei?
A = -λN
Where λ is the decay constant
What are the decay equations?
A = A°e^-λt
N = N°e^-λt
What is the activity of a radioactive nuclei?
The rate of decay of a sample of radioactive nuclei
What is the equation for finding the number of unstable nuclei after a time t, if the number of half lives is known?
N = N°/2^x
A = A°/2^x
What is the equation for half life?
T = ln(2)/λ
What is activity measured in?
Bq (becquerels)
What is the decay constant?
The probability that a single nucleus will decay per unit time
What is true about energy and mass?
They are equivalent:
E = mc^2
In a nuclear reaction the energy produced is equivalent to what?
The energy produced is equivalent to the loss of mass
What is binding energy?
The energy that has to be supplied to separate a nucleus into its individual nucleons
What is a nucleon?
A proton or neutron
What is true with a higher the binding energy of a nuclei?
The more stable the nuclei is
Why are nuclei with a higher binding energy per nucleon more stable?
Because the binding energy per nucleon is energy required to overcome the strong nuclear force holding the nuclei’s nucleons together
What happens when you input the binding energy to separate nucleons?
The separated nucleons have a slight increase in mass
In both fusion and fission reactions what is true about the binding energy per nucleon of the product?
The binding energy per nucleon of the product is higher than the reactants
How much energy is one “u” equal to?
931 MeV
What is the mass defect?
The mass of a nucleus is smaller than the sum of the masses of the constituent nucleons, this difference is the mass defect
