Nuclear Physics Flashcards
Mass defect, binding energy, nuclear fission, nuclear fusion, half-life, activity, decay constant.
Binding energy of a nucleus
Energy needed to separate to infinity the nucleons in a nucleus.
Binding energy per nucleon
Energy needed to separate to infinity the nucleons in a nucleus divided by the number of nucleons in the nucleus.
Nuclear fusion
Light nuclei combine to form a heavier nucleus.
Nuclear fission
The splitting of a heavy nucleus into two lighter nuclei of approximately the same mass.
Explain what is meant by “nuclear decay is spontaneous”.
The decay is not affected by external factors, such as temperature or pressure.
Explain what is meant by “nuclear decay is random”.
It is impossible to predict which nucleus will decay next. However, there is a constant probability of decay per unit time of a nucleus.
Decay constant
The probability that a particular nucleus will decay per unit time.
Activity
The number of nuclei decaying per unit time.
Half-life
The time taken for the number of undecayed nuclei to reduce to half the initial number.
Mass defect of a nucleus
mass defect = total mass of the separate nucleons - combined mass of the nucleus.
Einstein’s mass-energy equation
E = mc^2
This equation shows that mass and energy are equivalent or interchangeable.
Electron-volt
One electron-volt is the energy gained by one electron when it is accelerated through a potential difference of one volt.
1 eV = 1.60 x 10^-19 J
The most stable nuclide is _______
Iron-56
The binding energy per nucleon is a useful measure of _________
the stability of the nucleus.
Unit of activity
Bq
An activity of one decay per second is 1 Bq.
