# Topic Questions: 104 be able to use the equation $Q=Q_{0}e^{-t/RC}$ and derive and use related equations for exponential discharge in a resistor-capacitor circuit, $I=I_{0}e^{-t/RC}$ and $V=V_{0}e^{-t/RC}$ and the corresponding log equations $\ln Q=\ln Q_{0}-\frac{t}{RC}$, $\ln I=\ln I_{0}-\frac{t}{RC}$ and $\ln V=\ln V_{0}-\frac{t}{RC}$ — WPH14 Electric and Magnetic Fields

> 26 WPH14 Electric and Magnetic Fields topic questions (75 marks) on 104 be able to use the equation … and derive and… — 18 papers, 2020–2026. Open the exact…

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Edexcel IAL · Physics · WPH14 · Electric and Magnetic Fields

26 WPH14 Electric and Magnetic Fields topic questions are tagged to this syllabus point across 18 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.

- 26 topic questions
- 18 papers
- 75 tagged marks
- 8.6% of topic questions
- 9.7% of topic marks
- 2020–2026
- Syllabus 2018–current
- [All WPH14 Electric and Magnetic Fields topic questions](https://www.examsci.com/topics/edexcel-ial/physics/physics-unit-4-wph14/electric-and-magnetic-fields/)
- [All paper codes](https://www.examsci.com/topics/)

Core finding

**This Electric and Magnetic Fields syllabus point appears in 18 WPH14 papers across 2020–2026, contributing 26 topic questions and 75 marks.** The most recent appearance is WPH14/01 January 2026. That equals 8.6% of the 304 topic questions and 9.7% of the 770 marks tagged to Electric and Magnetic Fields. 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 |
| --- | --- | --- | --- | --- | --- | --- |
| [**WPH14/01** January 2026 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2026-january-wph14-01/#q-15) | **Q15** Defibrillator Capacitor Charging and Discharging - Edexcel IAL Physics Unit 4 Jan 2026 Q15 | FRQ | 3 of 4 parts ((b)(i), (b)(ii), (c)) | 9 of 12 on the paper | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=07537f0c-01cf-4760-bd10-3eed77f7d0a6&question_id=e332941f-d2c3-426e-a396-6d649e4e329f&source_detail=WPH14%2F01+January+2026) |
| [**WPH14/02** January 2026 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2026-january-wph14-02/#q-7) | **Q7** Capacitor Discharge Graph Interpretation - Edexcel IAL Physics Jan 2026 Q7 | MCQ | MCQ · 1 part | 1 | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=ee1f4910-5f08-42aa-b80e-e6f9fada0b73&question_id=dfaa3c19-97a9-413d-b426-2f07b0f55590&source_detail=WPH14%2F02+January+2026) |
| [**WPH14/02** January 2026 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2026-january-wph14-02/#q-19) | **Q19** Digital Coulombmeter and Capacitor Discharge - Edexcel IAL Physics Jan 2026 Q19 | FRQ | 1 of 5 parts ((b)(i)) | 3 of 9 on the paper | Easy | [Go to Practice Hub](https://www.examsci.com/practice?set_id=ee1f4910-5f08-42aa-b80e-e6f9fada0b73&question_id=49218c58-a9ad-4bbe-8bf6-a1a520cf50b8&source_detail=WPH14%2F02+January+2026) |
| [**WPH14/01** October 2025 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2025-october-wph14-01/#q-20) | **Q20** Touchscreen Capacitor Charge and Discharge - Edexcel IAL Physics Oct 2025 Q20 | 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=c925843a-0326-4cc4-a60c-ebad9960c7c0&question_id=3f6c9e5b-09a7-49ea-a799-3d993806461b&source_detail=WPH14%2F01+October+2025) |
| [**WPH14/02** October 2025 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2025-october-wph14-02/#q-15) | **Q15** Capacitor Charging and Discharging Analysis - Edexcel IAL Physics Oct 2025 Q15 | FRQ | 1 of 5 parts ((c)(i)) | 3 of 14 on the paper | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=19a8118b-74b7-4fe4-9125-57c7428661ba&question_id=cdc6a07e-7503-4d0c-b783-4e6efd0e5ed3&source_detail=WPH14%2F02+October+2025) |
| [**WPH14/01** June 2025 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2025-june-wph14-01/#q-17) | **Q17** Power Supply Output Smoothing - Edexcel IAL Physics June 2025 Q17 | FRQ | 1 of 4 parts ((b)(i)) | 5 of 12 on the paper | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=3fa77855-5a47-4e9d-9d77-8e6feeafb348&question_id=6524110e-448c-47de-be4a-2ab2738f99dc&source_detail=WPH14%2F01+June+2025) |
| [**WPH14/01** January 2025 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2025-january-wph14-01/#q-20) | **Q20** Capacitor Charging and Discharging Investigation - Edexcel IAL Physics Jan 2025 Q20 | FRQ | 2 of 6 parts ((b)(ii), (c)) | 7 of 18 on the paper | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=3fa71427-5fa5-4200-87e4-7de25234272d&question_id=2061c2f6-8f2e-4de3-a920-f23019fd5c33&source_detail=WPH14%2F01+January+2025) |
| [**WPH14/01** June 2024 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2024-june-wph14-01/#q-6) | **Q6** Time Constant Formula - Edexcel IAL Physics Unit 4 June 2024 Q6 | MCQ | MCQ · 1 part | 1 | Easy | [Go to Practice Hub](https://www.examsci.com/practice?set_id=cd6c5948-4054-4ae4-8638-e8fde551f1f4&question_id=05258ab4-5d59-4519-9606-8942e53170ef&source_detail=WPH14%2F01+June+2024) |
| [**WPH14/01** June 2024 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2024-june-wph14-01/#q-12) | **Q12** Investigation of Capacitor Charging - Edexcel IAL Physics Unit 4 June 2024 Q12 | FRQ | 1 of 4 parts ((b)(i)) | 3 of 9 on the paper | Easy | [Go to Practice Hub](https://www.examsci.com/practice?set_id=cd6c5948-4054-4ae4-8638-e8fde551f1f4&question_id=21d6a249-92ab-41dc-a9ad-5054cd12292b&source_detail=WPH14%2F01+June+2024) |
| [**WPH14/01** January 2024 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2024-january-wph14-01/#q-18) | **Q18** Charging a Capacitor in an RC Circuit - Edexcel IAL Physics Jan 2024 Q18 | FRQ | 1 of 3 parts ((a)(i)) | 4 of 10 on the paper | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=7f671b10-3bb0-47d7-9ab5-58b3498dd1dd&question_id=a53da636-c3fc-4004-825d-b63bde7cf66c&source_detail=WPH14%2F01+January+2024) |
| [**WPH14/01** October 2023 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2023-october-wph14-01/#q-9) | **Q9** Capacitor Discharge Time - Edexcel IAL Physics Oct 2023 Q9 | MCQ | MCQ · 1 part | 1 | Easy | [Go to Practice Hub](https://www.examsci.com/practice?set_id=63cf6d9e-c5b2-42b1-b898-7773fe6081a7&question_id=1665f0a7-50b4-4210-ab88-30258b2cb4a8&source_detail=WPH14%2F01+October+2023) |
| [**WPH14/01** October 2023 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2023-october-wph14-01/#q-18) | **Q18** Capacitor Discharge Evaluation - Edexcel IAL Physics Oct 2023 Q18 | FRQ | 1 of 2 parts ((a)) | 4 of 7 on the paper | Hard | [Go to Practice Hub](https://www.examsci.com/practice?set_id=63cf6d9e-c5b2-42b1-b898-7773fe6081a7&question_id=787179ee-674d-46d0-bb97-46b7fa461889&source_detail=WPH14%2F01+October+2023) |
| [**WPH14/01** June 2023 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2023-june-wph14-01/#q-18) | **Q18** Capacitor Timing Circuit and Collisions - Edexcel IAL Physics June 2023 Q18 | FRQ | 2 of 4 parts ((a), (b)(ii)) | 6 of 13 on the paper | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=2055a28e-816f-4ab5-8253-c37cfd7dd7b9&question_id=9c2eeb3b-111f-4b0e-a89f-27bf5ab565e8&source_detail=WPH14%2F01+June+2023) |
| [**WPH14/01** January 2023 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2023-january-wph14-01/#q-16) | **Q16** Capacitor Charging and Discharging - Edexcel IAL Physics Jan 2023 Q16 | FRQ | 1 of 4 parts ((b)(i)) | 3 of 12 on the paper | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=495cc00c-1d7f-4297-981d-c1c626ca134d&question_id=eea2354a-e708-4416-81ad-ea6abdc16f89&source_detail=WPH14%2F01+January+2023) |
| [**WPH14/01** October 2022 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2022-october-wph14-01/#q-12) | **Q12** Defibrillator Capacitor Circuits - Edexcel IAL Physics Oct 2022 Q12 | FRQ | 1 of 2 parts ((b)) | 4 of 8 on the paper | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=9be141d5-8b06-4cb6-8fa6-68d1cc9a6174&question_id=7b3fe7b2-4d40-4a62-a5d0-cacf560ea196&source_detail=WPH14%2F01+October+2022) |
| [**WPH14/01** June 2022 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2022-june-wph14-01/#q-15) | **Q15** RC Circuit Input Analysis - Edexcel IAL Physics June 2022 Q15 | FRQ | 2 of 4 parts ((a)(iii), (b)) | 5 of 9 on the paper | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=6042feb3-c856-448e-8691-d6933b5190bc&question_id=f4c5b7fe-8e24-4fb5-870b-5244e293afd2&source_detail=WPH14%2F01+June+2022) |
| [**WPH14/01** January 2022 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2022-january-wph14-01/#q-14) | **Q14** Capacitor Charging Circuit Analysis - Edexcel IAL Physics Jan 2022 Q14 | FRQ | 1 of 5 parts ((c)) | 3 of 11 on the paper | Easy | [Go to Practice Hub](https://www.examsci.com/practice?set_id=49fe32a1-ed2d-43cb-8e5c-01ad7a065d74&question_id=141eac29-e7a0-4f8a-b9d7-db09b52b65fe&source_detail=WPH14%2F01+January+2022) |
| [**WPH14/01** October 2021 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2021-october-wph14-01/#q-14) | **Q14** Model Railway Capacitor Circuit - Edexcel IAL Physics Oct 2021 Q14 | FRQ | 1 of 3 parts ((b)) | 2 of 9 on the paper | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=8cbfca05-d9d4-4992-a2fe-4a148f95c213&question_id=d561cc94-be34-4e35-9f1a-59b84e95a8af&source_detail=WPH14%2F01+October+2021) |
| [**WPH14/01** June 2021 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2021-june-wph14-01/#q-17) | **Q17** Capacitor Charging and Discharging - June 2021 Q17 | FRQ | 1 of 6 parts ((b)(ii)) | 3 of 16 on the paper | Easy | [Go to Practice Hub](https://www.examsci.com/practice?set_id=b192ea77-92eb-44fc-91ce-d3a09157fcbf&question_id=fa560af2-0056-436c-8290-dad0f853c348&source_detail=WPH14%2F01+June+2021) |
| [**WPH14/01** January 2021 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2021-january-wph14-01/#q-10) | **Q10** Capacitor Discharge Logarithmic Gradient - Edexcel IAL Physics Jan 2021 Q10 | MCQ | MCQ · 1 part | 1 | Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=ad4d3bdd-35e1-4b4e-8408-0afd068c0d8f&question_id=3823970a-0914-483e-a1b8-99dd3e5f7e3c&source_detail=WPH14%2F01+January+2021) |
| [**WPH14/01** January 2020 · Edexcel IAL](https://www.examsci.com/past-papers/edexcel-ial/physics/physics-unit-4-wph14/2020-january-wph14-01/#q-17) | **Q17** Night Light Capacitor Circuit - Edexcel IAL Physics Jan 2020 Q17 | FRQ | 1 of 3 parts ((a)) | 4 of 10 on the paper | Hard | [Go to Practice Hub](https://www.examsci.com/practice?set_id=5ef0bb69-523b-4ef4-b94b-964485f16e14&question_id=d9967806-fec6-4a82-a88c-0d630fa54df8&source_detail=WPH14%2F01+January+2020) |

## Related topic questions in Electric and Magnetic Fields

- [92 understand that an electric field (force field) is defined as a region where a charged particle experiences a force](https://www.examsci.com/topics/edexcel-ial/physics/physics-unit-4-wph14/electric-and-magnetic-fields/92-understand-that-an-electric-field-force-field-is-defined-as-a-region-where-a/) — 11 question items · 6 papers — 27 marks · 2020–2025
- [93 understand that electric field strength is defined as $E=\frac{F}{Q}$ and be able to use this equation](https://www.examsci.com/topics/edexcel-ial/physics/physics-unit-4-wph14/electric-and-magnetic-fields/93-understand-that-electric-field-strength-is-defined-as-e-frac-f-q-and-be-able-to/) — 30 question items · 17 papers — 93 marks · 2020–2026
- [94 be able to use the equation $F=\frac{Q_{1}Q_{2}}{4\pi\epsilon_{0}r^{2}}$ for the force between two charges](https://www.examsci.com/topics/edexcel-ial/physics/physics-unit-4-wph14/electric-and-magnetic-fields/94-be-able-to-use-the-equation-f-frac-q-1-q-2-4-pi-epsilon-0-r-2-for-the-force/) — 18 question items · 15 papers — 46 marks · 2020–2026
- [95 be able to use the equation $E=\frac{Q}{4\pi\epsilon_{0}r^{2}}$ for the electric field due to a point charge](https://www.examsci.com/topics/edexcel-ial/physics/physics-unit-4-wph14/electric-and-magnetic-fields/95-be-able-to-use-the-equation-e-frac-q-4-pi-epsilon-0-r-2-for-the-electric-field-due/) — 12 question items · 11 papers — 23 marks · 2020–2026
- [96 know and understand the relation between electric field and electric potential](https://www.examsci.com/topics/edexcel-ial/physics/physics-unit-4-wph14/electric-and-magnetic-fields/96-know-and-understand-the-relation-between-electric-field-and-electric-potential/) — 7 question items · 6 papers — 12 marks · 2021–2026
- [97 be able to use the equation $E=\frac{V}{d}$ for an electric field between parallel plates](https://www.examsci.com/topics/edexcel-ial/physics/physics-unit-4-wph14/electric-and-magnetic-fields/97-be-able-to-use-the-equation-e-frac-v-d-for-an-electric-field-between-parallel/) — 24 question items · 17 papers — 75 marks · 2020–2026

## Topic question rules and edge cases

**How many topic questions cover this syllabus point?**

21 question stems cover this subtopic across 18 papers, but only 26 tagged parts and 75 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.

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Full page with native tables, bar charts and Practice Hub links: https://www.examsci.com/topics/edexcel-ial/physics/physics-unit-4-wph14/electric-and-magnetic-fields/104-be-able-to-use-the-equation-q-q-0-e-t-rc-and-derive-and-use-related-equations-for/