Long answer·Standard multi-step (3/5)·Calculator allowed
Difficulty guide
The label describes the problem, not your ability.
1/5 - Foundational
Warm-up setup; checks one basic idea.
2/5 - Routine exam skill
Normal syllabus skill; usually one main rule or interpretation.
3/5 - Standard multi-step
Exam-style problem with multiple steps or a common trap.
4/5 - Hard exam skill
High-end exam problem; combines methods carefully.
5/5 - Challenge
Stretch problem beyond normal exam pressure.
Question
A pipe closed at one end has length . Take speed of sound as .
Total: 4 marks
(a) Find the fundamental frequency. (1 mark)
(b) Find the next two allowed frequencies. (1 mark)
(c) Find the wavelengths corresponding to these three frequencies. (1 mark)
(d) Explain why is not an allowed frequency. (1 mark)
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