Chapter 29 - Nuclear Physics

mass defect

the difference between the total mass of the individual separate nucleons and the mass of the nucleus

atomic mass unit

1/12 of the mass of a neutral atom of carbon-12

binding energy

the minimum external energy required to completely separate all the neutrons and protons of a nucleus to infinity

fission

the process in which a massive nucleus splits into two smaller nuclei

fusion

the process by which two very light nuclei join together to form a heavier nucleus

decay constant

the probability that an individual nucleus will decay per unit time interval

activity, A

the rate of decay of nuclei of a radioactive source

count rate

the number of particles (beta or alpha) or gamma-ray photons detected per unit time by a Geiger-Muller tube. Count rate is always a fraction of the activity of a sample

exponential decay

the decrease of a quantity where the rate of decrease is proportional to the value of the quantity

half-life

the half-life of an isotope is the mean time taken for half of the active nuclei in a sample to decay