Nuclear Decay Flashcards
Isotope
An element with the same number of protons, but a different number of neutrons
Nuclear Decay
Spontaneous emission of energy of alpha, beta, gamma by an unstable nucleus to become more stable
Half life
The time taken for the number of radioactive nuclei to halve
Decay constant
The fraction of nuclei that will decay per second
Activity
The rate of decay of a sample of radioactive nuclei
What unit is used for Activity
Becquerel (Bq)
What is an Alpha radiation particle
A helium nucleus
What is a Beta radiation particle
A High speed electron
What is Gamma radiation
An Electromagnetic Wave
What is the charge of an Alpha particle
2+
What is the charge of a Beta Particle
1-
What is the charge of a gamma wave
0
What is the definition of half life
The time taken for half the number of radioactive nuclei present to decay
What is the penetration, like of an Alpha particle
low
What is the penetration, like of a Beta particle
medium
What is the penetration, like of a Gamma wave
High
What is the change in nucleon and proton number when an Alpha particle is emitted
nucleon = -4
proton = -2
What is the change in nucleon and proton number when a Beta particle is emitted
nucleon = 0
proton = +1
Does Gamma radiation effect Nucleon and Proton Numbers, why?
No, since it does not have a charge
What types of radiation are effected by electric/magnetic fields
Alpha and Beta
Why do highly ionising particles have low penetration power
The particle interacts strongly with matter i passes through. So in each interaction some KE is absorbed by the matter. Which reduces its penetrating power.
What is the first reason Alpha particles are highly ionising when compared to Beta particles, why
They have a higher charge than Beta
So they interact more strongly with other charged particles
What is the second reason Alpha particles are highly ionising when compared to Beta particles, why
They have a larger mass
So they are more likely to collide with other particles
What is the Third reason Alpha particles are highly ionising when compared to Beta particles, why
They move slower
So they increase the likelihood of interacting with other particles
Why are gamma particles weakly ionising
They have no charge and no rest mass, High frequency so electrons cannot move fast enough to interact with them
Describe the theory behind the first method to distinguishing between the radiations.
The three radiations have different penetrating powers, we use this to filter the radiations, with a counter detecting changes.
Describe the theory behind the second method to distinguishing between the radiations
Since Alpha and Beta particles have opposite charges they move in different directions through electric/magnetic fields. A carefully placed Geiger counter can be used to detect the different radiations.
What is the equation for the activity of a radioactive nuclei
A = -λN
N = Number of nuclei
λ = Decay constant
What are the two similar equations that can be used to find the number of radioactive nuclei and activity
N = N_0e^(-λt)
A = A_0e^(-λt)
What is the equation for Decay constant
λ = (ln(2))/(half life)
