11.2 AS Level

Fundamental particles

8 flashcards to master this topic

Definition Flip

What are the six flavours (types) of quarks?

Answer Flip

The six flavours of quarks are: up, down, strange, charm, top, and bottom. These are fundamental particles.

Definition Flip

What is the charge of an up quark, and what is the charge of its corresponding antiquark?

Answer Flip

An up quark has a charge of +2/3 e. An anti-up quark has a charge of -2/3 e.

Key Concept Flip

Describe the quark composition of a proton and a neutron.

Answer Flip

A proton consists of two up quarks and one down quark (uud). A neutron consists of one up quark and two down quarks (udd).

Definition Flip

What distinguishes a baryon from a meson in terms of quark composition?

Answer Flip

A baryon is a hadron consisting of three quarks (qqq). A meson is a hadron consisting of one quark and one antiquark (q anti-q).

Key Concept Flip

Describe the change in quark composition during β- decay.

Answer Flip

During β- decay, a neutron (udd) converts into a proton (uud). One down quark changes into an up quark, emitting an electron and an antineutrino: d → u + e- + anti-νe.

Key Concept Flip

Describe the change in quark composition during β+ decay.

Answer Flip

During β+ decay, a proton (uud) converts into a neutron (udd). One up quark changes into a down quark, emitting a positron and a neutrino: u → d + e+ + νe.

Definition Flip

Name two fundamental particles that are classified as leptons.

Answer Flip

Electrons and neutrinos are examples of fundamental particles called leptons. They are not composed of quarks.

Key Concept Flip

Are protons and neutrons fundamental particles? Explain why or why not.

Answer Flip

Protons and neutrons are *not* fundamental particles. They are composite particles made of quarks (protons = uud, neutrons = udd). Fundamental particles are not made of smaller constituents.

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