You Gotta Know These Classes of Particles

The mass of particles is usually given in mega-electronvolts (MeV), where an electronvolt is the energy acquired by an electron when it crosses a potential difference of one volt. The energies are converted to masses by Einstein’s equation E = mc2, where c is the speed of light in a vacuum. Charges are given in terms of the fundamental electric charge (the absolute value of the charge on an electron).

Every kind of particle also has a corresponding anti-particle made of anti-matter; when it is said that there are (for instance) six leptons, anti-particles are not counted, so in some sense there are twelve). Anti-particles have the same mass, but the opposite charge, of the original. There are no particles with negative mass. Note that in some rare situations, a particle can be its own anti-particle.

Thumbs Up! for Science & Math

NAQT’s Thumbs Up! for Science & Math practice questions consist entirely of tossups and bonuses on science and mathematics.

Learn More Order Now

Browse More “You Gotta Know” Articles

There are over 100 other You Gotta Know articles — make sure you’re studying all of these important topics!

Browse Latest Articles Browse By Category