# Worksheet: Up Quarks and Down Quarks

In this worksheet, we will practice describing the properties of up and down quarks and the composition of protons and neutrons.

Q1:

How many quarks are there in a neutron?

Q2:

What is the relative charge of a down quark?

• A
• B
• C
• D1
• E

Q3:

How many quarks are there in a proton?

Q4:

The nucleus of a carbon-14 atom contains 6 protons and 8 neutrons.

How many up quarks are in the nucleus in total?

How many down quarks are in the nucleus in total?

Q5:

 Quark Up Down Relative Charge 23 −13

The table shows the relative charges of the up and down quarks. If a composite particle were made up of 3 up quarks, what would the relative charge of that composite particle be?

• A+2
• B+3
• C
• D+1
• E

Q6:

What is the relative charge of an up quark?

• A
• B
• C1
• D
• E

Q7:

QuarkRelative ChargeRelative Mass
Up
Down

A group of physicists detect a particle that has a relative charge of and a mass times the mass of a proton. Which of the following composite particles, made of up and down quarks, could the mysterious particle be?

• AThe particle cannot be any of these combinations.
• BUp, up, up, down, down
• CUp, up, up
• DUp, up, up, up, down
• EUp, down, down

Q8:

The diagram shows 4 composite particles. Each particle is made up of 3 quarks. Quarks with the letter u are up quarks, and quarks with the letter d are down quarks. Red particles are particles with a positive electric charge, and blue particles are particles with a negative electric charge.

Which of the 4 composite particles is a proton?

• A(c)
• B(a)
• C(b)
• D(d)
• ENone

Which of the 4 composite particles is a neutron?

• A(c)
• B(b)
• CNone
• D(a)
• E(d)

Q9:

The nucleus of a helium-4 atom contains 2 protons and 2 neutrons.

How many up quarks are in the nucleus in total?

How many down quarks are in the nucleus in total?

Q10:

 Quark Up Down Relative Charge 23 −13

The table shows the relative charges of the up and down quarks. If a composite particle were made up of 3 down quarks, what would the relative charge of that composite particle be?

Q11:

Which of the following is the correct symbol for an up quark?

• A
• B
• C
• D
• E

Q12:

Which of the following is the correct symbol for a down quark?

• A
• B
• C
• D
• E

Q13:

Which of the following particles are fundamental particles?

1. Up quarks
2. Neutrons
3. Positrons
4. Electrons
5. Protons
6. Down quarks
7. Alpha particles
• Aa, c, and d
• Ba, c, d, and f
• Ca and f
• Da, f, and c
• Eb, d, and e

Q14:

Which of the following particles are not fundamental particles?

1. Down quark
2. Positron
3. particle
4. Electron
5. Up quark
6. Neutron
7. Proton
• A(f), (g), and (d)
• B(g), (d), and (a)
• C(c), (f), and (g)
• D(e), (b), and (a)
• E(c), (f), and (a)