Important Equations

E  = Energy 

M = Mass

C = Speed of light


 N = A - Z

N = Number of Neutrons 

A = Atomic Mass Number 

Z = Atomic Number 

N (t) = Amount of radioactive material left after a given amount of time (could be a mass or percentage) 

No = Amount of radioactive material original started with (could be mass or 100%)

 = Decay rate, every radioactive material has it's own decay rate 

t = time 

  = Average life time of the particle, the mean life expectance  of a single particle.  This is not half life


Nuclear Physics Introduction


         Along with neutrons, protons make up the nucleus, held together by the strong force. The proton is a baryon and is considered to be composed of two up quarks and one down quark.


        Along with protons, neutrons make up the nucleus, held together by the strong force. The neutron is a baryon and is considered to be composed of two down quarks and one up quark.


Electron Volt

       The electron volt (symbol eV; also written electronvolt) is a unit of energy equal to approximately 1.602×10−19 J. By definition, it is equal to the amount of kinetic energy gained by a single unbound electron when it accelerates through an electric potential difference of one volt. Thus it is 1 volt (1 joule per coulomb) multiplied by the positive equivalent of the charge of a single electron (1 e, or 1.6021765×10−19 C). Therefore, one electron volt is equal to 1.60217653×10−19 J.


The Atom

Atomic Mass

      In Physics, the mass number (A), also called atomic mass number or nucleon number, is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus. The mass number is different for each different isotope of a chemical element. This is not the same as the atomic number (Z) which denotes the number of protons in a nucleus, and thus uniquely identifies an element. Hence, the difference between the mass number and the atomic number gives the number of neutrons (N) in a given nucleus:          N=A−Z.

Definitions Provided by Wikipedia


Atomic Number

       In physics, the atomic number (also known as the proton number) is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus. It is conventionally represented by the symbol Z

Definition provided by Wikipedia



        Isotopes are different types of atoms (nuclides) of the same chemical element, each having a different number of neutrons. In a corresponding manner, isotopes differ inmass number (or number of nucleons) but never in atomic number.  The number of protons (the atomic number) is the same because that is what characterizes a chemical element. For example, carbon-12, carbon-13 and carbon-14 are three isotopes of the element carbon with mass numbers 12, 13 and 14, respectively. Theatomic number of carbon is 6, so the neutron numbers in these isotopes of carbon are therefore 12−6 = 6, 13−6 = 7, and 14–6 = 8, respectively.

Definition provided by Wikipedia