Question:
It is now believed that protons and neutrons (which constitute nuclei of ordinary matter) are themselves built out of more elementary units called quarks. A proton and a neutron consist of three quarks each. Two types of quarks, the so called up quark (denoted by u) of charge + (2/3) e, and the down quark (denoted by d) of charge (-1/3) e, together with electrons build up ordinary matter. (Quarks of other types have also been found which give rise to different unusual varieties of matter.) Suggest a possible quark composition of a proton and neutron.
Answer:
A proton has three quarks. Let there be n up quarks in a proton, each having a charge of
.
Charge due to n up quarks
Number of down quarks in a proton = 3 – n
Each down quark has a charge of 
.
Charge due to (3 – n) down quarks 
Total charge on a proton = + e
Number of up quarks in a proton, n = 2
Number of down quarks in a proton = 3 – n = 3 – 2 = 1
Therefore, a proton can be represented as
A neutron also has three quarks. Let there be n up quarks in a neutron, each having a charge of 
.
Charge on a neutron due to n up quarks 
Number of down quarks is 3 – n, each having a charge of 
.
Charge on a neutron due to 
down quarks = 
Total charge on a neutron = 0
Number of up quarks in a neutron, n = 1
Number of down quarks in a neutron = 3 – n = 2
Therefore, a neutron can be represented as
.
Not what you are looking for? Go ahead and submit the question, we will get back to you.
