Every charge you have met is a whole number on the proton's scale: +1 for the proton, −1 for the electron, 0 for the neutron. The quarks inside a proton break that pattern.
In earlier grades you saw that charge comes in two kinds, and that on the scale physicists use, the proton's charge is +1 and the electron's charge is −1. Quark charges sit on the same scale, where the proton's charge is +1.
The up quark carries a charge of +2/3. The down quark carries a charge of −1/3. Both are fractions of the proton's charge. These are the first particles you have met whose charge is not a whole number.
On the proton-equals-+1 scale, what charge does the down quark carry?
Which quark carries a charge of +2/3?
Ana says the down quark's charge is −1, like the electron's. Is Ana correct?
On the proton-equals-+1 scale, which row pairs each quark with its charge correctly?
A particle data sheet lists a charge of −1/3 on the proton-equals-+1 scale. Which particle fits?
Which statement about quark charges is correct?