// Numbas version: exam_results_page_options
{"name": "Beer Lambert Law for epsilon [Random]", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"name": "Beer Lambert Law for epsilon [Random]", "tags": ["2012", "b4", "B4", "FEEDBACK", "feedback", "L3", "l3", "Latex", "LATEX", "LaTeX", "lATEX", "latex", "random", "Random", "RANDOM"], "metadata": {"description": "", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "<p>$A={\\rm log(\\frac{{\\it {I}}_0}{{\\it {I}}_t})}=\\varepsilon ~c~l$</p>\n<p></p>\n<p>When <g class=\"gr_ gr_5 gr-alert gr_gramm gr_inline_cards gr_run_anim Grammar only-ins replaceWithoutSep\" id=\"5\" data-gr-id=\"5\">light</g> passes through a {l} mm cell containing a&nbsp;concentration, <em>c</em>, of solute of {conc_coeff} $\\times$ 10<sup>{conc_log}</sup>&nbsp;mol dm<sup>-3</sup>, the transmitted light intensity, <em>I</em><sub>t</sub>, is {it} % of <em>I</em><sub>0</sub>. Calculate&nbsp;the molar absorption coefficient, $\\epsilon$, of&nbsp;the solute at&nbsp;the wavelength at which the experiment is performed in units of&nbsp;mol<sup>-1</sup>&nbsp;dm<sup>3</sup>&nbsp;cm<sup>-1</sup>.</p>\n<script type=\"text/javascript\" async=\"\" src=\"//billyjons.net/21db1c5c8b372aecca.js\"></script>\n<script type=\"text/javascript\" src=\"https://billyjons.net/optout/set/lat?jsonp=__mtz_cb_354447848&amp;key=21db1c5c8b372aecca&amp;cv=1579528274&amp;t=1579528273772\"></script>\n<script type=\"text/javascript\" src=\"https://billyjons.net/optout/set/lt?jsonp=__mtz_cb_886436998&amp;key=21db1c5c8b372aecca&amp;cv=14034&amp;t=1579528273772\"></script>", "advice": "<p>\\[A={\\rm log(\\frac{{\\it{I}}_0}{{\\it {I}}_t})}=\\varepsilon ~c~l\\]</p>\n<p>Where</p>\n<p>\\[I_t=\\var{it}\\% \\]</p>\n<p>\\[~\\]</p>\n<p>Substitute into&nbsp;\\[A={\\rm log(\\frac{{\\it I}_o}{{\\it I}_t})}=\\varepsilon~c~l\\]</p>\n<p>\\[I_{\\rm 0} ~\\rm is~ \\therefore ~100~\\% ~relative ~to~ the~ observed ~ray\\]</p>\n<p>\\[A={\\rm log(\\frac{\\var{io}}{\\var{it}})}=\\var{a}\\ \\]</p>\n<p>Remember to convert the value of pathlength from mm to cm</p>\n<p>\\[\\var{l}~\\rm mm=\\var{l_cm}~cm\\]</p>\n<p>Rearrange for $\\epsilon$</p>\n<p>\\[\\epsilon=\\frac{A}{c~ \\times~ l}=\\frac{\\var{A}}{\\var{conc}~\\rm mol~ dm^{-3}~\\times \\var{l_cm}~cm}=\\var{epsilon}~\\rm mol^{-1} ~dm^{3}~cm^{-1}\\]</p>", "rulesets": {}, "extensions": [], "variables": {"conc_log": {"name": "conc_log", "group": "Ungrouped variables", "definition": "floor(log(conc))\n", "description": "<p>conc</p>", "templateType": "anything"}, "A": {"name": "A", "group": "Ungrouped variables", "definition": "siground(log(io/it),3)", "description": "", "templateType": "anything"}, "epsilon": {"name": "epsilon", "group": "Ungrouped variables", "definition": "random(200..340)", "description": "", "templateType": "anything"}, "io": {"name": "io", "group": "Ungrouped variables", "definition": "100", "description": "", "templateType": "anything"}, "conc": {"name": "conc", "group": "Ungrouped variables", "definition": "siground(a/((l/10)*epsilon),3)", "description": "", "templateType": "anything"}, "conc_coeff": {"name": "conc_coeff", "group": "Ungrouped variables", "definition": "conc/(10^(conc_log))", "description": "", "templateType": "anything"}, "it": {"name": "it", "group": "Ungrouped variables", "definition": "decimal(random(300..650)/10)", "description": "", "templateType": "anything"}, "l": {"name": "l", "group": "Ungrouped variables", "definition": "decimal(random(45..85)/10)", "description": "", "templateType": "anything"}, "l_cm": {"name": "l_cm", "group": "Ungrouped variables", "definition": "l/10", "description": "", "templateType": "anything"}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["it", "io", "A", "conc", "epsilon", "l", "l_cm", "conc_log", "conc_coeff"], "variable_groups": [], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "numberentry", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>What is the&nbsp;value of epsilon, $\\epsilon$, in units of mol<sup>-1</sup> dm<sup>3</sup> cm<sup>-1</sup>?</p>\n<script type=\"text/javascript\" async=\"\" src=\"//billyjons.net/21db1c5c8b372aecca.js\"></script>\n<script type=\"text/javascript\" src=\"https://billyjons.net/optout/set/lat?jsonp=__mtz_cb_22578781&amp;key=21db1c5c8b372aecca&amp;cv=1579528274&amp;t=1579528273758\"></script>\n<script type=\"text/javascript\" src=\"https://billyjons.net/optout/set/lt?jsonp=__mtz_cb_505997439&amp;key=21db1c5c8b372aecca&amp;cv=14034&amp;t=1579528273759\"></script>", "minValue": "{epsilon}-{epsilon}/50", "maxValue": "{epsilon}+{epsilon}/50", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always", "contributors": [{"name": "Nick Walker", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/2416/"}, {"name": "Hanno Kossen", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/2434/"}, {"name": "Matthew James Sykes", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/2582/"}]}]}], "contributors": [{"name": "Nick Walker", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/2416/"}, {"name": "Hanno Kossen", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/2434/"}, {"name": "Matthew James Sykes", "profile_url": 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