Considering that an up quark has a charge of +2/3 and a down quark has a charge of -1/3, which of the following represents the correct quark combination for a proton?

Question

A) 2 down, 1 up
B) 0 up, 3 down
C) 3 down, 3 up
D) 2 up, 1 down

Answer 1

since the proton has a charge of +1, you want
2/3 + 2/3 - 1/3 = 1