Proton is a subatomic particle that makes up the nucleus of an atom along with the neutron. Elements are classified based on the number of protons in the nucleus. A proton is composed of two up quarks and one down quark held together by color force, which makes it a hadron. The two up quarks results in a positive charge of 1.60217 × 10−19 C, exactly opposite to that of an electron. The mass of a proton is 1.67262 × 10−27 kg.
Frequently Asked Questions
How protons and electrons have the same magnitude of the charge?
It is because the total charge of the three quarks that make up the proton becomes equivalent to that of an electron. The individual charge of the two up quarks is +2/3 e and that of a down quark is -1/3 e, which gives a total charge of +1 e for a proton. A neutron has two down quarks and one up quark, giving a total charge of 0. So to form a proton of charge +1 e, one of the two down quarks of neutron should be turned to an up quark and a charge of -1 e should be emitted. We can understand this a little from neutron decaying into a proton through beta decay. Neutron, with weak interaction, turns one of the two down quarks to up quarks to become a proton. In the process, neutron emits W- boson of -1 e, which then decays to electron and antineutrino. The higher rest mass of the neutron is also lost as the mass and kinetic energy of the emitted particles. Just like mass and energy, the charge should also be conserved. As an electron of -1 e and a neutrino is emitted, the proton must now have +1 e of charge. And if they were not equal, atoms we know today would not be stable.
What happens when you split a proton?
Splitting a proton with enough energy would result in quarks being separated from each other. According to quark confinement, no single quark can ever exist. As the proton is being split, the separation of quarks increases along with the constant strong interaction acting between them. This results in the elongation of gluon tubes. When this tubes snaps, quarks would instantaneously form an antiquark and binds to it forming a new hadron.
Where does the mass of the proton come from?
Protons are made up of quarks. Quarks are held together by the strong nuclear force, mediated by gluons. So most of the mass of the proton comes from the kinetic energy of the quarks and the binding energy that holds them together. The rest of the mass comes from the mass of the quarks.