# Topic Questions: 170 be able to use the equations for redshift $z=\frac{\Delta\lambda}{\lambda}\approx\frac{\Delta f}{f}\approx\frac{v}{c}$ for a source of electromagnetic radiation moving relative to an observer and $v= H_{0}d$ for objects at cosmological distances — WPH15 Astrophysics and Cosmology > 39 WPH15 Astrophysics and Cosmology topic questions (98 marks) on 170 be able to use the equations for redshift …… — 20 papers, 2020–2026. Open the exact… - Canonical HTML: https://www.examsci.com/topics/edexcel-ial/physics/physics-unit-5-wph15/astrophysics-and-cosmology/170-be-able-to-use-the-equations-for-redshift-z-frac-delta-lambda-lambda-approx-frac/ - Markdown mirror: https://www.examsci.com/topics/edexcel-ial/physics/physics-unit-5-wph15/astrophysics-and-cosmology/170-be-able-to-use-the-equations-for-redshift-z-frac-delta-lambda-lambda-approx-frac/index.md --- Edexcel IAL · Physics · WPH15 · Astrophysics and Cosmology 39 WPH15 Astrophysics and Cosmology topic questions are tagged to this syllabus point across 20 papers (2020–2026). Only the parts whose knowledge graph matches this syllabus statement are counted, and the table shows which parts of each question are involved. - 39 topic questions - 20 papers - 98 tagged marks - 12.9% of topic questions - 13.5% of topic marks - 2020–2026 - Syllabus 2018–current - [All WPH15 Astrophysics and Cosmology topic questions](https://www.examsci.com/topics/edexcel-ial/physics/physics-unit-5-wph15/astrophysics-and-cosmology/) - [All paper codes](https://www.examsci.com/topics/) Core finding **This Astrophysics and Cosmology syllabus point appears in 20 WPH15 papers across 2020–2026, contributing 39 topic questions and 98 marks.** The most recent appearance is WPH15/01 January 2026. That equals 12.9% of the 303 topic questions and 13.5% of the 725 marks tagged to Astrophysics and Cosmology. Only parts tagged to this subtopic are counted, so a four-part question can contribute one item and one part's marks. The table lists every matching question, its tagged parts and marks, with a link back to the paper page. Sessions are newest first, so the statement can be traced back through the full paper history. ## Topic questions by session Newest sessions first. Parts and marks count only the parts tagged to this subtopic; “x of y parts” shows how much of the question is tagged elsewhere. Select the paper cell to open the matching question on the paper page, or use **Go to Practice Hub** to answer that exact question in the Interactive Practice Hub. | Paper | Question | Type | Parts | Marks | Difficulty | Practice | | --- | --- | --- | --- | --- | --- | --- | | [**WPH15/01** January 2026 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2026-january-wph15-01/#q-11) | **Q11** Redshift and Galaxy Velocity - Edexcel IAL Physics Jan 2026 Q11 | FRQ | 1 part | 2 | Easy | [Go to Practice Hub](https://www.examsci.com/practice?set_id=33df4133-3f97-49c4-8770-848b232eb7b1&question_id=bc4e21c4-7a6d-46da-bdc0-e4df92576d21&source_detail=WPH15%2F01+January+2026) | | [**WPH15/02** January 2026 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2026-january-wph15-02/#q-12) | **Q12** Sun Angular Velocity Doppler Shift - Edexcel IAL Physics Jan 2026 Q12 | FRQ | 1 part | 3 | Easy | [Go to Practice Hub](https://www.examsci.com/practice?set_id=f63db731-6514-40da-90c9-5232288471cb&question_id=5e0c404d-c090-4ef6-bcb1-29999c0253cc&source_detail=WPH15%2F02+January+2026) | | [**WPH15/01** October 2025 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2025-october-wph15-01/#q-4) | **Q4** Astrophysics - Hubble Constant - Edexcel IAL Physics Oct 2025 Q4 | MCQ | MCQ · 1 part | 1 | Easy | [Go to Practice Hub](https://www.examsci.com/practice?set_id=a7fbae2d-76be-4ac0-9bd4-df3ed119c92f&question_id=97bacef9-d4a7-417e-90fc-ad4edd5884c9&source_detail=WPH15%2F01+October+2025) | | [**WPH15/01** October 2025 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2025-october-wph15-01/#q-12) | **Q12** Astrophysics - Doppler Effect - Edexcel IAL Physics Oct 2025 Q12 | FRQ | 1 part | 2 | Easy | [Go to Practice Hub](https://www.examsci.com/practice?set_id=a7fbae2d-76be-4ac0-9bd4-df3ed119c92f&question_id=70e5acad-17c6-4fb3-9190-be4bffeed8fc&source_detail=WPH15%2F01+October+2025) | | [**WPH15/02** October 2025 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2025-october-wph15-02/#q-4) | **Q4** Hubble Constant and Age of Universe - Edexcel IAL Physics Oct 2025 Q4 | MCQ | MCQ · 1 part | 1 | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=e7442241-a09d-4872-a697-6e37dca804e8&question_id=954f226b-6951-45f0-b8ce-c8df91fc1995&source_detail=WPH15%2F02+October+2025) | | [**WPH15/02** October 2025 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2025-october-wph15-02/#q-12) | **Q12** Andromeda Galaxy Doppler Velocity - Edexcel IAL Physics Oct 2025 Q12 | FRQ | 1 part | 2 | Easy | [Go to Practice Hub](https://www.examsci.com/practice?set_id=e7442241-a09d-4872-a697-6e37dca804e8&question_id=0f29c911-3085-42cc-8482-126aa3b61123&source_detail=WPH15%2F02+October+2025) | | [**WPH15/01** June 2025 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2025-june-wph15-01/#q-4) | **Q4** Hubble Constant - Edexcel IAL Physics June 2025 Q4 | MCQ | MCQ · 1 part | 1 | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=2e30fb2a-dfff-4c32-b30f-fefebd92c451&question_id=aec69f91-6c53-4014-837e-3e40d76b1905&source_detail=WPH15%2F01+June+2025) | | [**WPH15/01** June 2025 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2025-june-wph15-01/#q-5) | **Q5** Doppler Shift - Edexcel IAL Physics June 2025 Q5 | MCQ | MCQ · 1 part | 1 | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=2e30fb2a-dfff-4c32-b30f-fefebd92c451&question_id=e804dda3-d8f6-4d07-baa4-f2539d75fcd7&source_detail=WPH15%2F01+June+2025) | | [**WPH15/01** January 2025 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2025-january-wph15-01/#q-7) | **Q7** Hubble Constant and Age of Universe - Edexcel IAL Physics Jan 2025 Q7 | MCQ | MCQ · 1 part | 1 | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=40c335c3-e98a-43c8-b5d1-d1abedfaca1a&question_id=e0581ebe-f7b2-41e8-93d2-1c3d6c071335&source_detail=WPH15%2F01+January+2025) | | [**WPH15/01** January 2025 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2025-january-wph15-01/#q-18) | **Q18** Solar Absorption Lines and Doppler Effect - Edexcel IAL Physics Jan 2025 Q18 | FRQ | 1 of 2 parts ((b)) | 5 of 8 on the paper | Easy | [Go to Practice Hub](https://www.examsci.com/practice?set_id=40c335c3-e98a-43c8-b5d1-d1abedfaca1a&question_id=c7f8a050-cd4e-46f1-85cf-5ef534f5d45f&source_detail=WPH15%2F01+January+2025) | | [**WPH15/01** October 2024 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2024-october-wph15-01/#q-17) | **Q17** Edexcel IAL Physics Unit 5 Oct 2024 Q17 | FRQ | 2 of 3 parts ((a)(ii), (b)) | 6 of 8 on the paper | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=3e10632c-bdcc-44a6-afc4-5f4f7a30978e&question_id=3c2f2b67-23fa-4c47-a268-1522a3295791&source_detail=WPH15%2F01+October+2024) | | [**WPH15/01** June 2024 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2024-june-wph15-01/#q-16) | **Q16** Epsilon-Eridani Radiation and Doppler Shift - Edexcel IAL Physics Unit 5 Jun 2024 Q16 | FRQ | 1 of 2 parts ((b)) | 3 of 8 on the paper | Hard | [Go to Practice Hub](https://www.examsci.com/practice?set_id=fd4de767-0a74-4fd7-9f81-6fb7daf58d01&question_id=11cd64f5-49f2-4455-b234-7ac96b2ee4fb&source_detail=WPH15%2F01+June+2024) | | [**WPH15/01** January 2024 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2024-january-wph15-01/#q-13) | **Q13** Astrophysics and Cosmology - Edexcel IAL Physics Jan 2024 Q13 | FRQ | 1 part | 3 | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=81ae8d95-9845-43d2-85aa-56edeba0f606&question_id=1e340210-6d9d-4960-a848-ba811c98c94a&source_detail=WPH15%2F01+January+2024) | | [**WPH15/01** January 2024 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2024-january-wph15-01/#q-18) | **Q18** Astrophysics and Cosmology - Edexcel IAL Physics Jan 2024 Q18 | FRQ | 1 of 3 parts ((c)) | 4 of 11 on the paper | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=81ae8d95-9845-43d2-85aa-56edeba0f606&question_id=29f24309-77ef-4797-a253-2a2308af967b&source_detail=WPH15%2F01+January+2024) | | [**WPH15/01** October 2023 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2023-october-wph15-01/#q-14) | **Q14** Cosmological Redshift and Hubble's Law - Edexcel IAL Physics Oct 2023 Q14 | FRQ | 2 parts ((a), (b)) | 4 | Easy | [Go to Practice Hub](https://www.examsci.com/practice?set_id=c6d9493b-ab37-4b2a-967c-30f17fd52e71&question_id=2cca6434-f889-416e-8eac-74f5e2c8208f&source_detail=WPH15%2F01+October+2023) | | [**WPH15/01** October 2023 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2023-october-wph15-01/#q-21) | **Q21** Stellar Evolution and Mechanics of Betelgeuse - Edexcel IAL Physics Oct 2023 Q21 | FRQ | 1 of 4 parts ((b)) | 6 of 13 on the paper | Hard | [Go to Practice Hub](https://www.examsci.com/practice?set_id=c6d9493b-ab37-4b2a-967c-30f17fd52e71&question_id=20110155-de90-4b23-8957-730987f13d6f&source_detail=WPH15%2F01+October+2023) | | [**WPH15/01** June 2023 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2023-june-wph15-01/#q-2) | **Q2** Edexcel IAL Physics Unit 5 June 2023 Q2 | MCQ | MCQ · 1 part | 1 | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=25ca8d3d-f529-419a-8ab4-22f4c43251b4&question_id=6fd08a7c-50fc-4bce-8ad6-75f69d7252de&source_detail=WPH15%2F01+June+2023) | | [**WPH15/01** June 2023 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2023-june-wph15-01/#q-5) | **Q5** Edexcel IAL Physics Unit 5 June 2023 Q5 | MCQ | MCQ · 1 part | 1 | Easy | [Go to Practice Hub](https://www.examsci.com/practice?set_id=25ca8d3d-f529-419a-8ab4-22f4c43251b4&question_id=8b348902-2100-4a57-a294-32a98de94de7&source_detail=WPH15%2F01+June+2023) | | [**WPH15/01** January 2023 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2023-january-wph15-01/#q-13) | **Q13** Redshift and Hubble's Law for M87 - Edexcel IAL Physics Jan 2023 Q13 | FRQ | 1 part | 5 | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=79fd249d-5274-48b7-a2fe-e660c6fd21a0&question_id=90149ba7-df79-4260-b61f-8d8c0d1f9e2a&source_detail=WPH15%2F01+January+2023) | | [**WPH15/01** October 2022 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2022-october-wph15-01/#q-6) | **Q6** Hubble Constant Expression - Edexcel IAL Physics Oct 2022 Q6 | MCQ | MCQ · 1 part | 1 | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=11a7a1e1-92c0-4c27-923f-84fabaf236e5&question_id=1e258643-e3dc-4ad9-84d8-a00c5c25e766&source_detail=WPH15%2F01+October+2022) | | [**WPH15/01** October 2022 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2022-october-wph15-01/#q-15) | **Q15** Redshift and Galaxies - Edexcel IAL Physics Oct 2022 Q15 | FRQ | 3 parts ((a), (b), (c)) | 7 | Easy | [Go to Practice Hub](https://www.examsci.com/practice?set_id=11a7a1e1-92c0-4c27-923f-84fabaf236e5&question_id=c3a45b1d-b8d3-4901-abea-142cd450df31&source_detail=WPH15%2F01+October+2022) | | [**WPH15/01** June 2022 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2022-june-wph15-01/#q-12) | **Q12** Hubble Constant Conversion and Age of Universe - Edexcel IAL Physics Jun 2022 Q12 | FRQ | 3 parts ((a)(i), (a)(ii), (b)) | 6 | Easy | [Go to Practice Hub](https://www.examsci.com/practice?set_id=9a093fb4-7c1b-4987-9e36-33b3e20c2b25&question_id=082c7130-9f77-4980-879f-33fca8459db8&source_detail=WPH15%2F01+June+2022) | | [**WPH15/01** June 2022 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2022-june-wph15-01/#q-19) | **Q19** Mercury Atoms Spectrum and Star Chi Lupi Properties - Edexcel IAL Physics Jun 2022 Q19 | FRQ | 1 of 3 parts ((b)) | 4 of 8 on the paper | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=9a093fb4-7c1b-4987-9e36-33b3e20c2b25&question_id=daaa8595-95a7-4058-870a-5787a341ac7e&source_detail=WPH15%2F01+June+2022) | | [**WPH15/01** January 2022 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2022-january-wph15-01/#q-6) | **Q6** Cosmological Expansion Evidence - Edexcel IAL Physics Jan 2022 Q6 | MCQ | MCQ · 1 part | 1 | Easy | [Go to Practice Hub](https://www.examsci.com/practice?set_id=ba0935d7-8bd2-4880-a14a-07ef68b24285&question_id=747fc7ed-6cde-4415-b562-325622f0728c&source_detail=WPH15%2F01+January+2022) | | [**WPH15/02** January 2022 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2022-january-wph15-02/#q-12) | **Q12** Redshift and Distance of a Galaxy - Edexcel IAL Physics Jan 2022 Q12 | FRQ | 1 part | 3 | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=23304130-a638-4c40-b130-1921931842df&question_id=09a0bcee-c415-4f5d-bc60-9273842f9eb3&source_detail=WPH15%2F02+January+2022) | | [**WPH15/01** October 2021 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2021-october-wph15-01/#q-16) | **Q16** Solar Rotation and Doppler Shift - Edexcel IAL Physics Oct 2021 Unit 5 Q16 | FRQ | 2 of 3 parts ((a), (c)) | 5 of 7 on the paper | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=85f00adf-61bf-4290-b7e1-556838a91d6f&question_id=d669b742-8e87-40d2-a629-6ca0b0f51ed0&source_detail=WPH15%2F01+October+2021) | | [**WPH15/01** October 2021 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2021-october-wph15-01/#q-17) | **Q17** Trigonometric Parallax and Age of the Universe - Edexcel IAL Physics Oct 2021 Unit 5 Q17 | FRQ | 1 of 2 parts ((b)) | 4 of 7 on the paper | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=85f00adf-61bf-4290-b7e1-556838a91d6f&question_id=4ad14482-ee62-4213-a3d0-18636c78f3de&source_detail=WPH15%2F01+October+2021) | | [**WPH15/01** June 2021 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2021-june-wph15-01/#q-2) | **Q2** Hubble Constant History - Edexcel IAL Physics Jun 2021 Q2 | MCQ | MCQ · 1 part | 1 | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=ab093dfb-339d-4a8a-9997-6d539dfdc6b8&question_id=9510a065-e598-480f-9501-5309d1c71d1e&source_detail=WPH15%2F01+June+2021) | | [**WPH15/01** June 2021 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2021-june-wph15-01/#q-15) | **Q15** Stellar Surface Temperature and Doppler Redshift - Edexcel IAL Physics Jun 2021 Q15 | FRQ | 1 of 2 parts ((b)) | 5 of 8 on the paper | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=ab093dfb-339d-4a8a-9997-6d539dfdc6b8&question_id=54630a25-0349-4cfb-8dbc-44ec96f1f3ce&source_detail=WPH15%2F01+June+2021) | | [**WPH15/01** January 2021 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2021-january-wph15-01/#q-16) | **Q16** Cosmology - colliding galaxies NGC 6052 | FRQ | 1 of 3 parts ((a)(ii)) | 3 of 7 on the paper | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=2e0b1233-9e48-4222-bc71-6c120258396f&question_id=60cb4a72-5891-4f47-923d-c14a4fa7fee6&source_detail=WPH15%2F01+January+2021) | | [**WPH15/01** January 2021 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2021-january-wph15-01/#q-20) | **Q20** Astrophysics - H-R Diagram and Doppler shift | FRQ | 1 of 4 parts ((b)(i)) | 4 of 14 on the paper | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=2e0b1233-9e48-4222-bc71-6c120258396f&question_id=c4f591b9-065f-45b8-9c94-365df89ad383&source_detail=WPH15%2F01+January+2021) | | [**WPH15/01** October 2020 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-5-wph15/2020-october-wph15-01/#q-12) | **Q12** Doppler Shift due to Exoplanet - Edexcel IAL Physics Oct 2020 Q12 | FRQ | 1 of 2 parts ((b)) | 2 of 5 on the paper | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=1a3931f7-4a72-41eb-af5a-0d315b2148a6&question_id=7c20b143-ed58-4b30-925b-687201386176&source_detail=WPH15%2F01+October+2020) | ## Related topic questions in Astrophysics and Cosmology - [154 understand that a gravitational field (force field) is defined as a region where a mass experiences a force](https://www.examsci.com/topics/edexcel-ial/physics/physics-unit-5-wph15/astrophysics-and-cosmology/154-understand-that-a-gravitational-field-force-field-is-defined-as-a-region-where-a/) — 5 question items · 4 papers — 13 marks · 2021–2026 - 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[158 be able to use the equation $V_{grav}=\frac{-Gm}{r}$ for a radial gravitational field](https://www.examsci.com/topics/edexcel-ial/physics/physics-unit-5-wph15/astrophysics-and-cosmology/158-be-able-to-use-the-equation-v-grav-frac-gm-r-for-a-radial-gravitational-field/) — 29 question items · 19 papers — 61 marks · 2020–2026 - [159 be able to compare electric fields with gravitational fields](https://www.examsci.com/topics/edexcel-ial/physics/physics-unit-5-wph15/astrophysics-and-cosmology/159-be-able-to-compare-electric-fields-with-gravitational-fields/) — 5 question items · 5 papers — 11 marks · 2020–2025 ## Topic question rules and edge cases **How many topic questions cover this syllabus point?** 32 question stems cover this subtopic across 20 papers, but only 39 tagged parts and 98 marks belong to it. Other parts of the same questions are assessed under different statements and are excluded from this page. **Which papers include this subtopic?** The table lists every matching session from 2020–2026. Each row links to the question anchor on the paper page, where the full paper context and practice entry point are available. **Why can one question appear under several subtopics?** The parts of one question can assess different syllabus statements. Each part is counted under its own subtopics, so the same question stem can appear on several subtopic pages while each page lists only the parts and marks tagged to that statement. **Can I practise these questions with AI marking?** Yes. Open a paper from the table and use the Interactive Practice Hub entry point. The page itself is static HTML so search engines and retrieval agents can read the full question list without executing JavaScript. --- Full page with native tables, bar charts and Practice Hub links: https://www.examsci.com/topics/edexcel-ial/physics/physics-unit-5-wph15/astrophysics-and-cosmology/170-be-able-to-use-the-equations-for-redshift-z-frac-delta-lambda-lambda-approx-frac/