// Numbas version: exam_results_page_options {"name": "Lennard-Jones potential", "extensions": [], "custom_part_types": [], "resources": [["question-resources/right_LENNARD.jpg", "/srv/numbas/media/question-resources/right_LENNARD.jpg"], ["question-resources/rwrong_LENNARD_1.jpg", "/srv/numbas/media/question-resources/rwrong_LENNARD_1.jpg"], ["question-resources/rwrong_LENNARD_2.jpg", "/srv/numbas/media/question-resources/rwrong_LENNARD_2.jpg"], ["question-resources/Wrong_LENNARD.jpg", "/srv/numbas/media/question-resources/Wrong_LENNARD.jpg"], ["question-resources/rwrong_LENNARD_3.jpg", "/srv/numbas/media/question-resources/rwrong_LENNARD_3.jpg"], ["question-resources/WL.jpg", "/srv/numbas/media/question-resources/WL.jpg"], ["question-resources/WL1.jpg", "/srv/numbas/media/question-resources/WL1.jpg"], ["question-resources/WL2.jpg", "/srv/numbas/media/question-resources/WL2.jpg"], ["question-resources/WL3.jpg", "/srv/numbas/media/question-resources/WL3.jpg"]], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"name": "Lennard-Jones potential", "tags": [], "metadata": {"description": "Conceptual question, assess the form of potential functions. ", "licence": "None specified"}, "statement": "
After a laborious day working in the laboratory you and your laboratory partner come up with the following equation to try and explain bonding for neutral molecules:
\n\\begin{equation}
V(r)= \\left[ \\left( \\frac{A}{r}\\right)^{6} - \\left( \\frac{B}{r}\\right)^{14} \\right]
\\end{equation}
Are any of the terms in this equation incorrect?
", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["Both terms are correct", "The first term $(\\frac{A}{r})^{6}$ should have a different sign, but the other term is correct.", "The second term $(-\\frac{B}{r})^{14}$ should have a different sign but the other term is correct.", "Both terms should have a diffrent sign. "], "matrix": [0, 0, 0, "1"], "distractors": ["", "", "", ""]}, {"type": "m_n_2", "useCustomName": false, "customName": "", "marks": 0, "showCorrectAnswer": true, "showFeedbackIcon": true, "scripts": {}, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "adaptiveMarkingPenalty": 0, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "prompt": "If you believe the potential to be wrong how would you explain it to your partner. That is, what kind of reasoning would you use to demonstrate that the potential does or does not behave, physically, as you would expect it. You might choose more that one answer in this question.
Hint: Consider the behaviour of the potential as $r\\rightarrow 0$ and $r\\rightarrow \\infty$.
Here follow 4 different plots of the potential experienced between two neutral particles ($V(r)$) as a function of their distance (r).
\n\n\n1 | \n2 | \n
\n | \n |
3 | \n4 | \n
\n | \n |
Which of the figures above could represent the potential given in the question above.
", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["Figure 1", "Figure 2", "Figure 3", "Figure 4"], "matrix": ["1", "0", 0, 0], "distractors": ["", "", "", ""]}, {"type": "1_n_2", "useCustomName": false, "customName": "", "marks": 0, "showCorrectAnswer": true, "showFeedbackIcon": true, "scripts": {}, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "adaptiveMarkingPenalty": 0, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "prompt": "Which one of those figures could correspond to a Lennard-Jones potential.
", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["Figure 1", "Figure 2", "Figure 3", "Figure 4"], "matrix": [0, "1", 0, "0"], "distractors": ["", "", "", ""]}, {"type": "1_n_2", "useCustomName": false, "customName": "", "marks": 0, "showCorrectAnswer": true, "showFeedbackIcon": true, "scripts": {}, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "adaptiveMarkingPenalty": 0, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "prompt": "Which of the points a or b in the figures corresponds to the equilibrium position?
", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["Point a", "Point b"], "matrix": ["1", 0], "distractors": ["", ""]}, {"type": "jme", "useCustomName": false, "customName": "", "marks": "2", "showCorrectAnswer": true, "showFeedbackIcon": true, "scripts": {}, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "adaptiveMarkingPenalty": 0, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "prompt": "What is $r$ at point a for the potential given in this equation?
Write $r$ as a function of $A$ and $B$.