# 9702 P1 Doppler effect for sound waves Topic Questions > CIE IAL 9702 P1: every Doppler effect for sound waves topic question from 11 papers (2025–2026), grouped by syllabus point. 11 questions, 11 marks, with… - Canonical HTML: https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/doppler-effect-for-sound-waves/ - Markdown mirror: https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/doppler-effect-for-sound-waves/index.md --- CIE IAL · Physics · 9702 P1 · A Level Every 9702 P1 Doppler effect for sound waves topic question from the 2025–2027 syllabus, drawn from 11 papers (2025–2026) and grouped by syllabus point. Each row opens a page listing the exact question numbers, marks and a direct link into the paper. These are questions by topic, not full papers, so you can revise one topic at a time. - 9702 P1 - 2 subtopics - 11 topic questions - 11 papers - 11 tagged marks - [Back to Doppler effect for sound waves](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/doppler-effect-for-sound-waves/) - [All paper codes](https://www.examsci.com/topics/) Core finding **2 use the expression … for the observed frequency when a source of… is the most frequently assessed subtopic in Doppler effect for sound waves, with 11 topic questions and 11 marks across 11 papers.** 1 understand that when a source of sound waves moves… follows with 5 topic questions and 5 marks. The topic contains 2 subtopics, 11 topic questions and 11 marks in total. Rows count only the parts tagged to that subtopic, keep the same colour in both charts and repeat paper count, tagged marks and year range in the native table. ## Topic question count and mark distribution Subtopics are on the vertical axis and sorted from highest to lowest. Only the parts whose knowledge graph matches a subtopic are counted for it, and percentages are each row's share of the tagged total in that chart. A part tagged to several subtopics is counted in each bar, so the bars are not a partition of the topic total. ### Questions by subtopic question items - [2 use the expression $f_o = \frac{f_s v}{v \pm v_s}$ for the observed frequency when a source of sound waves moves relative to a stationary observer](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/doppler-effect-for-sound-waves/2-use-the-expression-f-o-frac-f-s-v-v-pm-v-s-for-the-observed-frequency-when-a-source/) (11 papers) — 11 · 68.8% - [1 understand that when a source of sound waves moves relative to a stationary observer, the observed frequency is different from the source frequency (understanding of the Doppler effect for a stationary source and a moving observer is not required)](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/doppler-effect-for-sound-waves/1-understand-that-when-a-source-of-sound-waves-moves-relative-to-a-stationary/) (5 papers) — 5 · 31.3% ### Marks by subtopic marks - [2 use the expression $f_o = \frac{f_s v}{v \pm v_s}$ for the observed frequency when a source of sound waves moves relative to a stationary observer](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/doppler-effect-for-sound-waves/2-use-the-expression-f-o-frac-f-s-v-v-pm-v-s-for-the-observed-frequency-when-a-source/) (11 papers) — 11 · 68.8% - [1 understand that when a source of sound waves moves relative to a stationary observer, the observed frequency is different from the source frequency (understanding of the Doppler effect for a stationary source and a moving observer is not required)](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/doppler-effect-for-sound-waves/1-understand-that-when-a-source-of-sound-waves-moves-relative-to-a-stationary/) (5 papers) — 5 · 31.3% ## Subtopic comparison matrix Curriculum order is by syllabus number, then alphabetically. Every row links to the matching past-paper question list. | Subtopic | Topic questions | Papers | Marks | Years | | | --- | --- | --- | --- | --- | --- | | **[1 understand that when a source of sound waves moves relative to a stationary observer, the observed frequency is different from the source frequency (understanding of the Doppler effect for a stationary source and a moving observer is not required)](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/doppler-effect-for-sound-waves/1-understand-that-when-a-source-of-sound-waves-moves-relative-to-a-stationary/)** | 5 | 5 | 5 | 2025–2026 | [Open topic questions](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/doppler-effect-for-sound-waves/1-understand-that-when-a-source-of-sound-waves-moves-relative-to-a-stationary/) | | **[2 use the expression $f_o = \frac{f_s v}{v \pm v_s}$ for the observed frequency when a source of sound waves moves relative to a stationary observer](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/doppler-effect-for-sound-waves/2-use-the-expression-f-o-frac-f-s-v-v-pm-v-s-for-the-observed-frequency-when-a-source/)** | 11 | 11 | 11 | 2025–2026 | [Open topic questions](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/doppler-effect-for-sound-waves/2-use-the-expression-f-o-frac-f-s-v-v-pm-v-s-for-the-observed-frequency-when-a-source/) | ## Browse every topic question - [1 understand that when a source of sound waves moves relative to a stationary observer, the observed frequency is different from the source frequency (understanding of the Doppler effect for a stationary source and a moving observer is not required)](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/doppler-effect-for-sound-waves/1-understand-that-when-a-source-of-sound-waves-moves-relative-to-a-stationary/) — 5 question items · 5 papers — 5 marks · 2025–2026 - [2 use the expression $f_o = \frac{f_s v}{v \pm v_s}$ for the observed frequency when a source of sound waves moves relative to a stationary observer](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/doppler-effect-for-sound-waves/2-use-the-expression-f-o-frac-f-s-v-v-pm-v-s-for-the-observed-frequency-when-a-source/) — 11 question items · 11 papers — 11 marks · 2025–2026 ## Other topics in 9702 P1 - [Atoms, nuclei and radiation 27 question items](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/atoms-nuclei-and-radiation/) - [Density and pressure 26 question items](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/density-and-pressure/) - [Diffraction 9 question items](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/diffraction/) - [Elastic and plastic behaviour 22 question items](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/elastic-and-plastic-behaviour/) - [Electric current 13 question items](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/electric-current/) - [Electromagnetic spectrum 9 question items](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/electromagnetic-spectrum/) - [Energy conservation 25 question items](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/energy-conservation/) - [Equations of motion 43 question items](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/equations-of-motion/) - [Equilibrium of forces 17 question items](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/equilibrium-of-forces/) - [Errors and uncertainties 16 question items](https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/errors-and-uncertainties/) ## Topic question rules and edge cases **How many subtopics does Doppler effect for sound waves contain?** This page lists 2 subtopics tagged to the current syllabus. They are ordered by syllabus number, then alphabetically, and each row opens a page of matching past-paper questions. **How are the subtopic question and mark totals calculated?** A multiple-choice question contributes one item and its marks to every subtopic it is tagged with. A structured question contributes one item per tagged part, and that part’s marks; untagged parts of the same question are not counted here. A part tagged to several subtopics therefore appears under each of them. **Why do some subtopics have no numbered prefix?** Practical-skills statements and some syllabus bullets are unnumbered. Numbered statements come first; unnumbered statements and ties are sorted alphabetically. **Is the LaTeX rendered without JavaScript?** Yes. Subtopics that contain formulas are converted to static KaTeX HTML during the build, and the KaTeX stylesheet is served from the same site. --- Full page with native tables, bar charts and Practice Hub links: https://www.examsci.com/topics/cie-ial/physics/9702-paper-1/doppler-effect-for-sound-waves/