11.2.2—The charge of each flavour of quark and understand that its respective
- Syllabus
- 9702–2028–2029
- Objective
- 11.2.2
- Level
- AS
Quark charge depends on flavour: up-type quarks are +2/3e and down-type are −1/3e
Up, charm and top quarks carry charge +2/3e; down, strange and bottom carry −1/3e.
Add constituent charges to find a hadron’s total charge, remembering that antiquarks have opposite charge.
A proton uud has charge +2/3+2/3−1/3=+1e; a neutron udd has total charge zero.
Fractional quark charges are allowed inside hadrons even though isolated everyday matter has integral net charge.
ConceptA-Level CAIE Physics AS