ull,{"backHref":"/gcse/physics/edexcel/questions","basePath":"/gcse/physics/edexcel/efficiency-and-energy-resources/questions","formulaUrl":null,"initialIndex":45,"initialQuestionWindow":[{"id":"97737063-7099-41be-82bb-a209b2e905b9","revisionId":"94b38c3a-07b7-488b-bf38-ab10e5c665dc","questionNumber":null,"questionType":"LA","specification":"An LED lamp transfers energy from an electrical supply as shown in the energy diagram below.\n\n![An energy flow diagram for an LED lamp. The input arrow on the left is labelled 'Total electrical energy supplied = 15,000 J'. This splits into two output arrows: a straight arrow pointing to the right is labelled 'Useful light energy = 6,000 J', and a downward arrow is labelled 'Wasted thermal energy = 9,000 J'.](https://assets.mathsgenie.co.uk/aqa-qb/6197a3de-de0d-49ae-b159-532c4fa80b61.png)","difficulty":2,"difficultyBand":"easy","totalMarks":2,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"faeb2d49-0a67-47b1-8232-1b725291b668","label":null,"content":"Calculate the efficiency of the LED lamp.\n\nUse the equation:\n\n$$\\text{efficiency} = \\frac{\\text{useful energy transferred by the device}}{\\text{total energy supplied to the device}}$$","markscheme":"- Substitutes correct values into the efficiency equation: $\\text{efficiency} = \\frac{6,000}{15,000}$ M1\n- Calculates the final value to obtain $0.4$ (or $40\\%$) A1","marks":2,"order":0,"markingRubric":null,"explanation":{"methods":[{"id":"efficiency_calculation","label":"Calculate the efficiency","steps":[{"type":"text","order":0,"title":"Identify the two energies","content":"Use the supplied energy-flow diagram. The **useful** output is light energy, so use $6{,}000\\ \\mathrm{J}$. The total energy supplied is $15{,}000\\ \\mathrm{J}$.\n\nDo not use the wasted thermal energy: efficiency compares useful output with the total input.","highlights":[{"text":"Useful light energy = 6,000 J","location":"specification"},{"text":"Total electrical energy supplied = 15,000 J","location":"specification"}]},{"type":"hyper_latex","block":{"nodes":[{"latex":"\\text{efficiency}=\\frac{\\text{useful energy transferred}}{\\text{total energy supplied}}"},{"latex":"\\text{efficiency}=\\frac{\\htmlData{anchor=useful}{6{,}000}}{\\htmlData{anchor=total}{15{,}000}}"}],"highlights":[{"color":"sky","style":"box","anchor":"useful"},{"color":"orange","style":"box","anchor":"total"}]},"order":1,"title":"Substitute the values","description":"Put the useful light energy on top and the total electrical energy supplied on the bottom. This correct substitution earns the first mark."},{"type":"text","order":2,"title":"Divide to finish","content":"Now evaluate the fraction:\n\n$$6{,}000 \\div 15{,}000 = 0.4$$\n\nSo the efficiency is $0.4$, or $40\\%$. This correct final value earns the second mark (A1)."}]}],"generatedAt":"2026-07-22T11:32:39.626Z","modelVersion":"gpt-5.6-terra+diagrams-1","explanationVersion":"v3"},"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"9fccbd96-a497-4f50-8978-bb2cdd417fb4","revisionId":"5e1be09e-1371-4de7-8f0a-b5c48d249c0a","questionNumber":null,"questionType":"LA","specification":"Kerosene is a fossil fuel that is burned in the turbofan engines of commercial passenger aircraft.","difficulty":3,"difficultyBand":"easy","totalMarks":2,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"ba9cbacc-55be-4fde-b2f5-d37477cb362f","label":null,"content":"State **two** ways that the burning of kerosene can be harmful to the environment.","markscheme":"- Releases carbon dioxide ($CO_2$), which is a greenhouse gas that traps thermal radiation, contributing to global warming or climate change. B1\n- Releases nitrogen oxides ($NO_x$) or sulfur dioxide ($SO_2$), which react with moisture in the atmosphere to cause acid rain. B1\n- Releases carbon particulates (soot) or produces high-altitude contrails (water vapour), which trap heat or cause global dimming. B1","marks":2,"order":0,"markingRubric":null,"explanation":{"methods":[{"i

Efficiency and energy resources

Question 35

Efficiency and energy resources Questions

Efficiency and energy resources

Question 35

Efficiency and energy resources Questions