The quark combination of a particle is sū - AQA - A-Level Physics - Question 12 - 2021 - Paper 1
Question 12
The quark combination of a particle is sū.
Which is true for this particle?
A It has a baryon number of 1
B It has a charge of -1.6 × 10⁻¹⁹ C.
C It is a pion.
D It ... show full transcript
Worked Solution & Example Answer:The quark combination of a particle is sū - AQA - A-Level Physics - Question 12 - 2021 - Paper 1
Step 1
A It has a baryon number of 1
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Answer
The particle with the quark combination sū is a meson, specifically a strange quark and an up quark. Mesons have a baryon number of 0, not 1, hence this statement is false.
Step 2
B It has a charge of -1.6 × 10⁻¹⁹ C.
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Answer
The combination of sū (strange and up) indicates a charge of +2/3 (from up quark) and -1/3 (from strange quark), resulting in an overall charge of +1/3. Therefore, this statement is false.
Step 3
C It is a pion.
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Answer
Pions specifically consist of an up quark and a down quark (π⁺ or π⁻), so the combination sū does not represent a pion. This statement is false.
Step 4
D It has a strangeness of -⅓.
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Answer
The strange quark contributes a strangeness of -1, while the up quark contributes 0. Therefore, the strangeness of this particle is -1, making this statement false.
