OCR A-Level Physics B H557
Planning
Implementing
Analysis
Evaluation
Practical Skills
Use of Apparatus and Techniques
Fundamental Data Analysis
Imaging and Signalling
Sensing
Mechanical Properties of Materials
Waves and Quantum Behaviour
Space, Time and Motion
Creating Models
Out Into Space
Our Place in the Universe
Matter: Very Simple
Matter: Hot or Cold
Electromagnetism
Charge and Field
Probing Deep Into Matter
Ionising Radiation and Risk
Probing Deep Into Matter
Quarks, hadrons and leptons
- 3 things to know
- Components 01, 02 and 03
Overview
Recall questions on the quark compositions and charges of protons, neutrons and antiprotons, the charges of up and down quarks, hadrons, leptons and gluons, antiparticles and the positron, lepton numbers, neutrinos and why they are hard to detect, why free quarks are never seen, and beta-minus decay at quark level.
What you need to know
Answer each one before you reveal it.
State the quark composition of a neutron.
State the charges of the up quark and the down quark.
Questions from this subtopic
Each one with the model answer underneath.
- 1
State the quark composition of a proton.
Model answer
A proton is made of two up quarks and one down quark.
- 2
State the quark composition of a neutron.
Model answer
A neutron is made of one up quark and two down quarks.
- 3
State the charges of the up quark and the down quark.
Model answer
The up quark carries +2/3 of the elementary charge and the down quark carries −1/3 of it.
- 4
Show that the quark composition of a proton gives it a charge of +1e.
Model answer
Two up quarks and one down quark give +2/3 + 2/3 − 1/3, which is +1 in units of the elementary charge.
- 5
Show that the quark composition of a neutron gives it zero charge.
Model answer
One up quark and two down quarks give +2/3 − 1/3 − 1/3, which is zero.
- 6
What is a hadron?
Model answer
A hadron is a particle built from quarks that feels the strong interaction, and protons and neutrons are the familiar examples.
Other ways to work this
The same content, four other ways.
What is inside Levo
Six ways to work the same material.
Every question in Probing Deep Into Matter, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
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