Total charge on a proton =+ e
Number of up quarks in aproton, n = 2
Number of down quarks in aproton = 3 − n = 3 − 2 = 1
Therefore, a proton can berepresented as ‘uud’.
Aneutron also has three quarks. Let there be n up quarks in aneutron, each having a charge of
Charge on a neutron due to n upquarks
Number of down quarks is 3 − n,each havinga charge of
Charge on a neutron due to down quarks =
Total charge on a neutron= 0
Number of up quarks in aneutron, n = 1
Number of down quarks in aneutron = 3 − n = 2
Therefore,a neutron can be represented as ‘udd’.