Fundamental Forces

#physics#radiation


Strong Force#card §

The strongest fundamental force is the force that holds the nucleus together, binding quarks and holding nucleons together. This has a strength of 1 and the exchange particle is a gluon. It has a range of $10^{-15}$ (a medium sized nucleus) and ∴ larger sized nuclei decay.

• The strong nuclear force is so short range that its attraction can only be between adjacent nucleons
• Think of the force like a spring linking nucleons, the harder you try to pull them, the more the spring reacts to hold them together until they are separated by too much  and the spring snaps. The particles go out of reach of the attractive nature of the strong nuclear force and repel away from each other by the electromagnetic force.


Stable isotopes usually require the strong force to be slightly stronger than the electrostatic force within the nucleus. This means the nucleus is more attracted to itself than it is repelled by itself.

Electro-magnetic Force#card §

The force that attracts opposite charges and repels like charges. It has a strength of $\frac{1}{137}$ and a range of infinity, and it has a greater effect than the strong force beyond a certain range, causing decayed nuclei to repel each other (alpha decay). Exchange particle is a proton.

Weak Force#card §

The force that allows quarks to rearrange themselves, so neutrino (short lived fundamental particle) interaction induces beta decay. The weak force changes the spin of quarks, but essentially it causes beta decay. Exchange particles are W and Z bosons. It has a strength of $10^{-6}$ and a range of $10^{-18}$ (0.1% of the diameter of a proton)

Gravity#card §

Any objects of mass are attracted to each other. This is gravity, and is the weakest force, with a strength of $6\times 10^{-39}$ and range of $\infty$