{"id":5475,"date":"2026-10-26T20:50:59","date_gmt":"2026-10-26T15:20:59","guid":{"rendered":"https:\/\/johnsonfrancis.org\/horticulture\/?p=5475"},"modified":"2026-10-26T21:01:56","modified_gmt":"2026-10-26T15:31:56","slug":"physics-electricity-magnetism-mcqs-2","status":"publish","type":"post","link":"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/","title":{"rendered":"Physics: Electricity &amp; Magnetism MCQs &#8211; 2"},"content":{"rendered":"\n<!-- Secure MathJax Script with SRI -->\n<script>\n  window.MathJax = {\n    tex: { inlineMath: [['$', '$'], ['\\\\(', '\\\\)']], displayMath: [['$$', '$$'], ['\\\\[', '\\\\]']] }\n  };\n<\/script>\n<script id=\"MathJax-script\" async src=\"https:\/\/cdn.jsdelivr.net\/npm\/mathjax@3\/es5\/tex-mml-chtml.js\" integrity=\"sha384-r+VZXRfhtWtV\/Xtc5iAG5kMv73FV826qjE69K5T6Bq6O\/m2nS2wBmwR1P\/FfF6X\/\" crossorigin=\"anonymous\"><\/script>\n\n<!-- Quiz Container -->\n<div id=\"em-quiz-container\" class=\"em-quiz-wrapper\">\n    <div class=\"em-quiz-header\">\n        <div class=\"em-quiz-title\">\n            <h2>Physics: Electricity &#038; Magnetism (Part 2)<\/h2>\n            \n        <\/div>\n        <div class=\"em-timer-box\">\n            <span class=\"em-timer-label\">Time Remaining<\/span>\n            <div id=\"em-timer-display\">10:00<\/div>\n        <\/div>\n    <\/div>\n\n    <div class=\"em-quiz-bar\">\n        <span id=\"em-progress-text\">10 Questions<\/span>\n        <button type=\"button\" id=\"em-start-btn\">Start Quiz<\/button>\n    <\/div>\n\n    <form id=\"em-quiz-form\">\n        <!-- Question 1 -->\n        <div class=\"em-q-card\" data-q=\"1\">\n            <div class=\"em-q-number\">Question 1<\/div>\n            <div class=\"em-q-text\">A parallel plate capacitor with air between plates has capacitance <em>C<\/em>. If a dielectric slab of dielectric constant <em>K = 4<\/em> and thickness <em>t = d\/2<\/em> (where <em>d<\/em> is plate separation) is inserted, the new capacitance becomes:<\/div>\n            <div class=\"em-options\">\n                <label><input type=\"radio\" name=\"q1\" value=\"A\"> A) $\\frac{4}{5}C$<\/label>\n                <label><input type=\"radio\" name=\"q1\" value=\"B\"> B) $\\frac{8}{5}C$<\/label>\n                <label><input type=\"radio\" name=\"q1\" value=\"C\"> C) $2C$<\/label>\n                <label><input type=\"radio\" name=\"q1\" value=\"D\"> D) $4C$<\/label>\n            <\/div>\n            <div class=\"em-explanation\" id=\"exp-1\">\n                <strong>Correct Answer: B ($\\frac{8}{5}C$)<\/strong><br>\n                <em>Formula:<\/em> $C&#8217; = \\frac{\\epsilon_0 A}{d &#8211; t + \\frac{t}{K}}$. Substituting $t = \\frac{d}{2}$ and $K = 4$:<br>\n                $C&#8217; = \\frac{\\epsilon_0 A}{d &#8211; \\frac{d}{2} + \\frac{d}{8}} = \\frac{\\epsilon_0 A}{\\frac{5d}{8}} = \\frac{8}{5} \\frac{\\epsilon_0 A}{d} = \\frac{8}{5}C$.\n            <\/div>\n        <\/div>\n\n        <!-- Question 2 -->\n        <div class=\"em-q-card\" data-q=\"2\">\n            <div class=\"em-q-number\">Question 2<\/div>\n            <div class=\"em-q-text\">A magnetic dipole of magnetic moment <em>M<\/em> is rotated through $180^\\circ$ from the direction of a uniform magnetic field <em>B<\/em>. The work done in rotating the dipole is:<\/div>\n            <div class=\"em-options\">\n                <label><input type=\"radio\" name=\"q2\" value=\"A\"> A) $-MB$<\/label>\n                <label><input type=\"radio\" name=\"q2\" value=\"B\"> B) Zero<\/label>\n                <label><input type=\"radio\" name=\"q2\" value=\"C\"> C) $MB$<\/label>\n                <label><input type=\"radio\" name=\"q2\" value=\"D\"> D) $2MB$<\/label>\n            <\/div>\n            <div class=\"em-explanation\" id=\"exp-2\">\n                <strong>Correct Answer: D ($2MB$)<\/strong><br>\n                <em>Explanation:<\/em> Work done $W = -MB(\\cos\\theta_2 &#8211; \\cos\\theta_1)$. Here $\\theta_1 = 0^\\circ$ and $\\theta_2 = 180^\\circ$.<br>\n                $W = -MB(\\cos 180^\\circ &#8211; \\cos 0^\\circ) = -MB(-1 &#8211; 1) = 2MB$.\n            <\/div>\n        <\/div>\n\n        <!-- Question 3 -->\n        <div class=\"em-q-card\" data-q=\"3\">\n            <div class=\"em-q-number\">Question 3<\/div>\n            <div class=\"em-q-text\">The self-inductance $L$ of a long solenoid having $N$ turns, length $l$, and cross-sectional area $A$ is directly proportional to:<\/div>\n            <div class=\"em-options\">\n                <label><input type=\"radio\" name=\"q3\" value=\"A\"> A) $N$<\/label>\n                <label><input type=\"radio\" name=\"q3\" value=\"B\"> B) $N^2$<\/label>\n                <label><input type=\"radio\" name=\"q3\" value=\"C\"> C) $\\frac{1}{N}$<\/label>\n                <label><input type=\"radio\" name=\"q3\" value=\"D\"> D) $\\sqrt{N}$<\/label>\n            <\/div>\n            <div class=\"em-explanation\" id=\"exp-3\">\n                <strong>Correct Answer: B ($N^2$)<\/strong><br>\n                <em>Explanation:<\/em> Self-inductance of a solenoid is given by $L = \\frac{\\mu_0 N^2 A}{l}$. Hence, $L \\propto N^2$.\n            <\/div>\n        <\/div>\n\n        <!-- Question 4 -->\n        <div class=\"em-q-card\" data-q=\"4\">\n            <div class=\"em-q-number\">Question 4<\/div>\n            <div class=\"em-q-text\">The Quality Factor ($Q$-factor) of a series LCR resonant circuit is expressed as:<\/div>\n            <div class=\"em-options\">\n                <label><input type=\"radio\" name=\"q4\" value=\"A\"> A) $\\frac{1}{R}\\sqrt{\\frac{L}{C}}$<\/label>\n                <label><input type=\"radio\" name=\"q4\" value=\"B\"> B) $\\frac{1}{L}\\sqrt{\\frac{R}{C}}$<\/label>\n                <label><input type=\"radio\" name=\"q4\" value=\"C\"> C) $R\\sqrt{\\frac{C}{L}}$<\/label>\n                <label><input type=\"radio\" name=\"q4\" value=\"D\"> D) $\\frac{1}{C}\\sqrt{\\frac{L}{R}}$<\/label>\n            <\/div>\n            <div class=\"em-explanation\" id=\"exp-4\">\n                <strong>Correct Answer: A ($\\frac{1}{R}\\sqrt{\\frac{L}{C}}$)<\/strong><br>\n                <em>Explanation:<\/em> $Q = \\frac{\\omega_0 L}{R}$. Since resonant angular frequency $\\omega_0 = \\frac{1}{\\sqrt{LC}}$, substituting gives $Q = \\frac{1}{R}\\sqrt{\\frac{L}{C}}$.\n            <\/div>\n        <\/div>\n\n        <!-- Question 5 -->\n        <div class=\"em-q-card\" data-q=\"5\">\n            <div class=\"em-q-number\">Question 5<\/div>\n            <div class=\"em-q-text\">A potentiometer wire of length 10 m has a resistance of 20 \u03a9. It is connected in series with a 3V battery and a resistance of 10 \u03a9. The potential gradient along the wire is:<\/div>\n            <div class=\"em-options\">\n                <label><input type=\"radio\" name=\"q5\" value=\"A\"> A) 0.1 V\/m<\/label>\n                <label><input type=\"radio\" name=\"q5\" value=\"B\"> B) 0.2 V\/m<\/label>\n                <label><input type=\"radio\" name=\"q5\" value=\"C\"> C) 0.3 V\/m<\/label>\n                <label><input type=\"radio\" name=\"q5\" value=\"D\"> D) 0.5 V\/m<\/label>\n            <\/div>\n            <div class=\"em-explanation\" id=\"exp-5\">\n                <strong>Correct Answer: B (0.2 V\/m)<\/strong><br>\n                <em>Calculation:<\/em> Total resistance $R_{total} = 20 + 10 = 30\\,\\Omega$. Circuit current $I = \\frac{3\\text{ V}}{30\\,\\Omega} = 0.1\\text{ A}$.<br>\n                Voltage across wire $V_{wire} = I \\times R_{wire} = 0.1 \\times 20 = 2\\text{ V}$.<br>\n                Potential gradient $k = \\frac{V_{wire}}{L} = \\frac{2\\text{ V}}{10\\text{ m}} = 0.2\\text{ V\/m}$.\n            <\/div>\n        <\/div>\n\n        <!-- Question 6 -->\n        <div class=\"em-q-card\" data-q=\"6\">\n            <div class=\"em-q-number\">Question 6<\/div>\n            <div class=\"em-q-text\">What is the electric potential at any point on the equatorial plane of an electric dipole?<\/div>\n            <div class=\"em-options\">\n                <label><input type=\"radio\" name=\"q6\" value=\"A\"> A) Maximum<\/label>\n                <label><input type=\"radio\" name=\"q6\" value=\"B\"> B) Dependent on dipole distance<\/label>\n                <label><input type=\"radio\" name=\"q6\" value=\"C\"> C) Zero<\/label>\n                <label><input type=\"radio\" name=\"q6\" value=\"D\"> D) Infinite<\/label>\n            <\/div>\n            <div class=\"em-explanation\" id=\"exp-6\">\n                <strong>Correct Answer: C (Zero)<\/strong><br>\n                <em>Explanation:<\/em> Every point on the equatorial line is equidistant from both $+q$ and $-q$ charges of the dipole. The potential contributions $V_+ = \\frac{kq}{r}$ and $V_- = -\\frac{kq}{r}$ sum up to zero.\n            <\/div>\n        <\/div>\n\n        <!-- Question 7 -->\n        <div class=\"em-q-card\" data-q=\"7\">\n            <div class=\"em-q-number\">Question 7<\/div>\n            <div class=\"em-q-text\">A conducting rod of length $L$ rotates with constant angular velocity $\\omega$ about one end in a uniform magnetic field $B$ perpendicular to the plane of rotation. The induced EMF between its ends is:<\/div>\n            <div class=\"em-options\">\n                <label><input type=\"radio\" name=\"q7\" value=\"A\"> A) $BL\\omega$<\/label>\n                <label><input type=\"radio\" name=\"q7\" value=\"B\"> B) $\\frac{1}{2}BL^2\\omega$<\/label>\n                <label><input type=\"radio\" name=\"q7\" value=\"C\"> C) $B^2 L \\omega$<\/label>\n                <label><input type=\"radio\" name=\"q7\" value=\"D\"> D) $\\frac{1}{2}BL\\omega^2$<\/label>\n            <\/div>\n            <div class=\"em-explanation\" id=\"exp-7\">\n                <strong>Correct Answer: B ($\\frac{1}{2}BL^2\\omega$)<\/strong><br>\n                <em>Explanation:<\/em> Linear velocity varies from $0$ at the axis to $\\omega L$ at the tip. Average linear speed $v_{avg} = \\frac{\\omega L}{2}$. Motional EMF $e = B \\cdot v_{avg} \\cdot L = \\frac{1}{2} B L^2 \\omega$.\n            <\/div>\n        <\/div>\n\n        <!-- Question 8 -->\n        <div class=\"em-q-card\" data-q=\"8\">\n            <div class=\"em-q-number\">Question 8<\/div>\n            <div class=\"em-q-text\">If the electric flux entering and leaving a closed surface are $\\Phi_1$ and $\\Phi_2$ respectively, the net charge enclosed inside the surface is:<\/div>\n            <div class=\"em-options\">\n                <label><input type=\"radio\" name=\"q8\" value=\"A\"> A) $(\\Phi_2 &#8211; \\Phi_1)\\epsilon_0$<\/label>\n                <label><input type=\"radio\" name=\"q8\" value=\"B\"> B) $(\\Phi_1 + \\Phi_2)\\epsilon_0$<\/label>\n                <label><input type=\"radio\" name=\"q8\" value=\"C\"> C) $\\frac{\\Phi_2 &#8211; \\Phi_1}{\\epsilon_0}$<\/label>\n                <label><input type=\"radio\" name=\"q8\" value=\"D\"> D) $\\frac{\\epsilon_0}{\\Phi_2 &#8211; \\Phi_1}$<\/label>\n            <\/div>\n            <div class=\"em-explanation\" id=\"exp-8\">\n                <strong>Correct Answer: A ($(\\Phi_2 &#8211; \\Phi_1)\\epsilon_0$)<\/strong><br>\n                <em>Explanation:<\/em> Net outward electric flux $\\Phi_{net} = \\Phi_2 &#8211; \\Phi_1$. By Gauss&#8217;s Law, $\\Phi_{net} = \\frac{q_{enclosed}}{\\epsilon_0} \\implies q_{enclosed} = (\\Phi_2 &#8211; \\Phi_1)\\epsilon_0$.\n            <\/div>\n        <\/div>\n\n        <!-- Question 9 -->\n        <div class=\"em-q-card\" data-q=\"9\">\n            <div class=\"em-q-number\">Question 9<\/div>\n            <div class=\"em-q-text\">A step-up transformer has a turn ratio of $1:10$. If an alternating voltage of $220\\text{ V}$ is applied across the primary winding, the secondary voltage will be:<\/div>\n            <div class=\"em-options\">\n                <label><input type=\"radio\" name=\"q9\" value=\"A\"> A) 22 V<\/label>\n                <label><input type=\"radio\" name=\"q9\" value=\"B\"> B) 110 V<\/label>\n                <label><input type=\"radio\" name=\"q9\" value=\"C\"> C) 220 V<\/label>\n                <label><input type=\"radio\" name=\"q9\" value=\"D\"> D) 2200 V<\/label>\n            <\/div>\n            <div class=\"em-explanation\" id=\"exp-9\">\n                <strong>Correct Answer: D (2200 V)<\/strong><br>\n                <em>Explanation:<\/em> Transformer ratio $\\frac{V_s}{V_p} = \\frac{N_s}{N_p} = 10 \\implies V_s = 10 \\times 220\\text{ V} = 2200\\text{ V}$.\n            <\/div>\n        <\/div>\n\n        <!-- Question 10 -->\n        <div class=\"em-q-card\" data-q=\"10\">\n            <div class=\"em-q-number\">Question 10<\/div>\n            <div class=\"em-q-text\">The frequency of gyration (cyclotron frequency) of a charged particle moving in a uniform magnetic field is independent of its:<\/div>\n            <div class=\"em-options\">\n                <label><input type=\"radio\" name=\"q10\" value=\"A\"> A) Mass<\/label>\n                <label><input type=\"radio\" name=\"q10\" value=\"B\"> B) Charge<\/label>\n                <label><input type=\"radio\" name=\"q10\" value=\"C\"> C) Speed<\/label>\n                <label><input type=\"radio\" name=\"q10\" value=\"D\"> D) Magnetic field strength<\/label>\n            <\/div>\n            <div class=\"em-explanation\" id=\"exp-10\">\n                <strong>Correct Answer: C (Speed)<\/strong><br>\n                <em>Explanation:<\/em> Cyclotron frequency $f = \\frac{qB}{2\\pi m}$. It depends on $q$, $B$, and $m$, but is independent of the particle&#8217;s speed or radius of orbit.\n            <\/div>\n        <\/div>\n\n        <div class=\"em-action-box\">\n            <button type=\"button\" id=\"em-submit-btn\" disabled>Submit Answers<\/button>\n            <button type=\"button\" id=\"em-reset-btn\">Reset Quiz<\/button>\n        <\/div>\n    <\/form>\n\n    <div id=\"em-results-box\" class=\"em-results-card\" style=\"display: none;\">\n        <h3>Quiz Results<\/h3>\n        <div class=\"em-score-summary\">\n            <div class=\"em-score-circle\" id=\"em-score-circle\">0\/10<\/div>\n            <div class=\"em-score-details\">\n                <p id=\"em-score-text\">You scored 0 out of 10<\/p>\n                <p id=\"em-feedback-msg\">Press Start to attempt!<\/p>\n            <\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<style>\n\/* Same CSS as before *\/\n.em-quiz-wrapper { font-family: -apple-system, BlinkMacSystemFont, \"Segoe UI\", Roboto, Helvetica, Arial, sans-serif; max-width: 800px; margin: 20px auto; padding: 20px; background: #ffffff; border: 1px solid #e2e8f0; border-radius: 12px; box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05); box-sizing: border-box; }\n.em-quiz-header { display: flex; justify-content: space-between; align-items: center; border-bottom: 2px solid #0056b3; padding-bottom: 12px; margin-bottom: 15px; flex-wrap: wrap; gap: 10px; }\n.em-quiz-title h2 { margin: 0; color: #0056b3; font-size: 1.4rem; }\n.em-quiz-title p { margin: 4px 0 0 0; font-size: 0.88rem; color: #64748b; }\n.em-timer-box { background: #1e293b; color: #ffffff; padding: 8px 16px; border-radius: 8px; text-align: center; min-width: 110px; }\n.em-timer-label { display: block; font-size: 0.68rem; text-transform: uppercase; letter-spacing: 0.5px; color: #94a3b8; }\n#em-timer-display { font-size: 1.4rem; font-weight: 700; font-family: monospace; color: #38bdf8; }\n.em-quiz-bar { display: flex; justify-content: space-between; align-items: center; background: #f8fafc; padding: 10px 16px; border-radius: 6px; margin-bottom: 20px; font-weight: 600; color: #334155; }\n#em-start-btn { background: #0284c7; color: white; border: none; padding: 8px 18px; border-radius: 6px; font-weight: 600; cursor: pointer; transition: background 0.2s; }\n#em-start-btn:hover { background: #0369a1; }\n.em-q-card { background: #ffffff; border: 1px solid #cbd5e1; border-radius: 8px; padding: 18px; margin-bottom: 16px; transition: border-color 0.2s; }\n.em-q-card.correct { border-left: 6px solid #16a34a; background: #f0fdf4; }\n.em-q-card.incorrect { border-left: 6px solid #dc2626; background: #fef2f2; }\n.em-q-number { font-size: 0.78rem; font-weight: 700; color: #0284c7; text-transform: uppercase; margin-bottom: 6px; }\n.em-q-text { font-size: 1rem; font-weight: 600; color: #1e293b; margin-bottom: 12px; line-height: 1.5; }\n.em-options label { display: block; background: #f8fafc; border: 1px solid #e2e8f0; padding: 10px 14px; border-radius: 6px; margin-bottom: 8px; cursor: pointer; font-size: 0.95rem; color: #334155; transition: background 0.15s, border-color 0.15s; }\n.em-options label:hover { background: #f1f5f9; border-color: #cbd5e1; }\n.em-options input[type=\"radio\"] { margin-right: 10px; }\n.em-explanation { display: none; margin-top: 12px; padding: 12px; background: #ffffff; border: 1px dashed #94a3b8; border-radius: 6px; font-size: 0.88rem; color: #334155; line-height: 1.5; }\n.em-action-box { display: flex; gap: 12px; margin-top: 20px; }\n#em-submit-btn, #em-reset-btn { flex: 1; padding: 12px; font-size: 1rem; font-weight: 600; border-radius: 6px; border: none; cursor: pointer; }\n#em-submit-btn { background: #16a34a; color: white; }\n#em-submit-btn:disabled { background: #9ca3af; cursor: not-allowed; }\n#em-submit-btn:hover:not(:disabled) { background: #15803d; }\n#em-reset-btn { background: #64748b; color: white; }\n#em-reset-btn:hover { background: #475569; }\n.em-results-card { margin-top: 25px; padding: 20px; background: #f0f9ff; border: 2px solid #0284c7; border-radius: 10px; text-align: center; }\n.em-results-card h3 { margin-top: 0; color: #0369a1; }\n.em-score-summary { display: flex; align-items: center; justify-content: center; gap: 20px; margin-top: 15px; flex-wrap: wrap; }\n.em-score-circle { width: 90px; height: 90px; border-radius: 50%; background: #0284c7; color: white; display: flex; align-items: center; justify-content: center; font-size: 1.4rem; font-weight: 700; }\n.em-score-details { text-align: left; }\n.em-score-details p { margin: 4px 0; font-weight: 600; }\n<\/style>\n\n<script>\n\/\/ Encapsulate inside DOMContentLoaded to ensure elements exist before binding\ndocument.addEventListener('DOMContentLoaded', function() {\n    \n    \/\/ Answers encoded in Base64 (A = QQ==, B = Qg==, C = Qw==, D = RA==)\n    const emAnswerKey = {\n        q1: 'Qg==', q2: 'RA==', q3: 'Qg==', q4: 'QQ==', q5: 'Qg==', \n        q6: 'Qw==', q7: 'Qg==', q8: 'QQ==', q9: 'RA==', q10: 'Qw=='\n    };\n\n    let emTimerInterval = null;\n    let emTimeLeft = 600; \n    let emQuizActive = false;\n\n    const startBtn = document.getElementById('em-start-btn');\n    const submitBtn = document.getElementById('em-submit-btn');\n    const resetBtn = document.getElementById('em-reset-btn');\n\n    \/\/ Secure Event Listeners (removes need for inline onclick attributes)\n    startBtn.addEventListener('click', function() {\n        if (emQuizActive) return;\n        emQuizActive = true;\n        emTimeLeft = 600;\n        submitBtn.disabled = false;\n        startBtn.disabled = true;\n        startBtn.innerText = \"Quiz in Progress\";\n        document.getElementById('em-results-box').style.display = 'none';\n\n        emTimerInterval = setInterval(function() {\n            emTimeLeft--;\n            let minutes = Math.floor(emTimeLeft \/ 60);\n            let seconds = emTimeLeft % 60;\n            document.getElementById('em-timer-display').innerText = \n                (minutes < 10 ? '0' : '') + minutes + ':' + (seconds < 10 ? '0' : '') + seconds;\n\n            if (emTimeLeft <= 0) {\n                clearInterval(emTimerInterval);\n                alert(\"Time's up! Submitting your answers automatically.\");\n                processSubmit();\n            }\n        }, 1000);\n    });\n\n    function processSubmit() {\n        if (!emQuizActive &#038;&#038; emTimeLeft > 0) return;\n        clearInterval(emTimerInterval);\n        emQuizActive = false;\n        submitBtn.disabled = true;\n        startBtn.disabled = false;\n        startBtn.innerText = \"Re-Start Quiz\";\n\n        let score = 0;\n        const total = 10;\n        const form = document.getElementById('em-quiz-form');\n\n        for (let i = 1; i <= total; i++) {\n            const qKey = 'q' + i;\n            \/\/ Get selected value if radio is checked, otherwise empty string\n            const selectedOption = form.elements[qKey].value || \"\";\n            const card = document.querySelector(`.em-q-card[data-q=\"${i}\"]`);\n            const explanation = document.getElementById(`exp-${i}`);\n\n            if (explanation) explanation.style.display = 'block';\n\n            \/\/ Convert selected letter to Base64 to compare against obfuscated key\n            if (selectedOption !== \"\" &#038;&#038; btoa(selectedOption) === emAnswerKey[qKey]) {\n                score++;\n                card.classList.remove('incorrect');\n                card.classList.add('correct');\n            } else {\n                card.classList.remove('correct');\n                card.classList.add('incorrect');\n            }\n        }\n\n        const resultsBox = document.getElementById('em-results-box');\n        document.getElementById('em-score-circle').innerText = `${score}\/${total}`;\n        document.getElementById('em-score-text').innerText = `You scored ${score} out of ${total} (${(score\/total)*100}%)`;\n        const feedbackMsg = document.getElementById('em-feedback-msg');\n\n        if (score >= 8) {\n            feedbackMsg.innerText = \"Excellent! Outstanding grasp of Electricity & Magnetism concepts.\";\n            feedbackMsg.style.color = \"#16a34a\";\n        } else if (score >= 5) {\n            feedbackMsg.innerText = \"Good effort! Review the step-by-step explanations below to strengthen key areas.\";\n            feedbackMsg.style.color = \"#d97706\";\n        } else {\n            feedbackMsg.innerText = \"Needs revision. Focus on fundamental formulas and attempt again!\";\n            feedbackMsg.style.color = \"#dc2626\";\n        }\n\n        resultsBox.style.display = 'block';\n        resultsBox.scrollIntoView({ behavior: 'smooth' });\n    }\n\n    submitBtn.addEventListener('click', processSubmit);\n\n    resetBtn.addEventListener('click', function() {\n        clearInterval(emTimerInterval);\n        emQuizActive = false;\n        emTimeLeft = 600;\n        document.getElementById('em-timer-display').innerText = \"10:00\";\n        startBtn.disabled = false;\n        startBtn.innerText = \"Start Quiz\";\n        submitBtn.disabled = true;\n        document.getElementById('em-quiz-form').reset();\n        document.getElementById('em-results-box').style.display = 'none';\n\n        for (let i = 1; i <= 10; i++) {\n            const card = document.querySelector(`.em-q-card[data-q=\"${i}\"]`);\n            const explanation = document.getElementById(`exp-${i}`);\n            if (card) card.classList.remove('correct', 'incorrect');\n            if (explanation) explanation.style.display = 'none';\n        }\n    });\n});\n<\/script>\n","protected":false},"excerpt":{"rendered":"<p>Physics: Electricity &#038; Magnetism (Part 2) Time Remaining 10:00 10 Questions Start Quiz Question 1 A parallel plate capacitor with air between plates has capacitance C. If a dielectric slab of dielectric constant K = 4 and thickness t = d\/2 (where d is plate separation) is inserted, the new capacitance becomes: A) $\\frac{4}{5}C$ B) [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":5476,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[],"class_list":["post-5475","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-vegetables-at-home"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v26.9 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Physics: Electricity &amp; Magnetism MCQs - 2 - Johnson&#039;s TechNAgro<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Physics: Electricity &amp; Magnetism MCQs - 2 - Johnson&#039;s TechNAgro\" \/>\n<meta property=\"og:description\" content=\"Physics: Electricity &#038; Magnetism (Part 2) Time Remaining 10:00 10 Questions Start Quiz Question 1 A parallel plate capacitor with air between plates has capacitance C. If a dielectric slab of dielectric constant K = 4 and thickness t = d\/2 (where d is plate separation) is inserted, the new capacitance becomes: A) $frac{4}{5}C$ B) [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/\" \/>\n<meta property=\"og:site_name\" content=\"Johnson&#039;s TechNAgro\" \/>\n<meta property=\"article:published_time\" content=\"2026-10-26T15:20:59+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2026-10-26T15:31:56+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/johnsonfrancis.org\/horticulture\/wp-content\/uploads\/2026\/10\/Physics-Electricity-and-Magnetism-MCQs-2.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"1208\" \/>\n\t<meta property=\"og:image:height\" content=\"675\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"author\" content=\"Johnson Francis\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Johnson Francis\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"4 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/\"},\"author\":{\"name\":\"Johnson Francis\",\"@id\":\"https:\/\/johnsonfrancis.org\/horticulture\/#\/schema\/person\/c3636df643ae569b05229e17c67a85f1\"},\"headline\":\"Physics: Electricity &amp; Magnetism MCQs &#8211; 2\",\"datePublished\":\"2026-10-26T15:20:59+00:00\",\"dateModified\":\"2026-10-26T15:31:56+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/\"},\"wordCount\":763,\"publisher\":{\"@id\":\"https:\/\/johnsonfrancis.org\/horticulture\/#\/schema\/person\/c3636df643ae569b05229e17c67a85f1\"},\"image\":{\"@id\":\"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/johnsonfrancis.org\/horticulture\/wp-content\/uploads\/2026\/10\/Physics-Electricity-and-Magnetism-MCQs-2.jpg\",\"articleSection\":[\"Vegetables at home\"],\"inLanguage\":\"en-US\"},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/\",\"url\":\"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/\",\"name\":\"Physics: Electricity &amp; Magnetism MCQs - 2 - Johnson&#039;s TechNAgro\",\"isPartOf\":{\"@id\":\"https:\/\/johnsonfrancis.org\/horticulture\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/#primaryimage\"},\"image\":{\"@id\":\"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/johnsonfrancis.org\/horticulture\/wp-content\/uploads\/2026\/10\/Physics-Electricity-and-Magnetism-MCQs-2.jpg\",\"datePublished\":\"2026-10-26T15:20:59+00:00\",\"dateModified\":\"2026-10-26T15:31:56+00:00\",\"breadcrumb\":{\"@id\":\"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/#primaryimage\",\"url\":\"https:\/\/johnsonfrancis.org\/horticulture\/wp-content\/uploads\/2026\/10\/Physics-Electricity-and-Magnetism-MCQs-2.jpg\",\"contentUrl\":\"https:\/\/johnsonfrancis.org\/horticulture\/wp-content\/uploads\/2026\/10\/Physics-Electricity-and-Magnetism-MCQs-2.jpg\",\"width\":1208,\"height\":675},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/johnsonfrancis.org\/horticulture\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Physics: Electricity &amp; Magnetism MCQs &#8211; 2\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/johnsonfrancis.org\/horticulture\/#website\",\"url\":\"https:\/\/johnsonfrancis.org\/horticulture\/\",\"name\":\"Johnson's Horticulture\",\"description\":\"Johnson&#039;s TechNAgro\",\"publisher\":{\"@id\":\"https:\/\/johnsonfrancis.org\/horticulture\/#\/schema\/person\/c3636df643ae569b05229e17c67a85f1\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/johnsonfrancis.org\/horticulture\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":[\"Person\",\"Organization\"],\"@id\":\"https:\/\/johnsonfrancis.org\/horticulture\/#\/schema\/person\/c3636df643ae569b05229e17c67a85f1\",\"name\":\"Johnson Francis\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/johnsonfrancis.org\/horticulture\/#\/schema\/person\/image\/\",\"url\":\"https:\/\/johnsonfrancis.org\/horticulture\/wp-content\/uploads\/2025\/01\/channels4_profile-1.jpg\",\"contentUrl\":\"https:\/\/johnsonfrancis.org\/horticulture\/wp-content\/uploads\/2025\/01\/channels4_profile-1.jpg\",\"width\":600,\"height\":600,\"caption\":\"Johnson Francis\"},\"logo\":{\"@id\":\"https:\/\/johnsonfrancis.org\/horticulture\/#\/schema\/person\/image\/\"},\"sameAs\":[\"https:\/\/johnsonfrancis.org\/horticulture\",\"https:\/\/www.youtube.com\/@JohnsonsHorticulture\/\"],\"url\":\"https:\/\/johnsonfrancis.org\/horticulture\/author\/jf\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Physics: Electricity &amp; Magnetism MCQs - 2 - Johnson&#039;s TechNAgro","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/","og_locale":"en_US","og_type":"article","og_title":"Physics: Electricity &amp; Magnetism MCQs - 2 - Johnson&#039;s TechNAgro","og_description":"Physics: Electricity &#038; Magnetism (Part 2) Time Remaining 10:00 10 Questions Start Quiz Question 1 A parallel plate capacitor with air between plates has capacitance C. If a dielectric slab of dielectric constant K = 4 and thickness t = d\/2 (where d is plate separation) is inserted, the new capacitance becomes: A) $frac{4}{5}C$ B) [&hellip;]","og_url":"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/","og_site_name":"Johnson&#039;s TechNAgro","article_published_time":"2026-10-26T15:20:59+00:00","article_modified_time":"2026-10-26T15:31:56+00:00","og_image":[{"width":1208,"height":675,"url":"https:\/\/johnsonfrancis.org\/horticulture\/wp-content\/uploads\/2026\/10\/Physics-Electricity-and-Magnetism-MCQs-2.jpg","type":"image\/jpeg"}],"author":"Johnson Francis","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Johnson Francis","Est. reading time":"4 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/#article","isPartOf":{"@id":"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/"},"author":{"name":"Johnson Francis","@id":"https:\/\/johnsonfrancis.org\/horticulture\/#\/schema\/person\/c3636df643ae569b05229e17c67a85f1"},"headline":"Physics: Electricity &amp; Magnetism MCQs &#8211; 2","datePublished":"2026-10-26T15:20:59+00:00","dateModified":"2026-10-26T15:31:56+00:00","mainEntityOfPage":{"@id":"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/"},"wordCount":763,"publisher":{"@id":"https:\/\/johnsonfrancis.org\/horticulture\/#\/schema\/person\/c3636df643ae569b05229e17c67a85f1"},"image":{"@id":"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/#primaryimage"},"thumbnailUrl":"https:\/\/johnsonfrancis.org\/horticulture\/wp-content\/uploads\/2026\/10\/Physics-Electricity-and-Magnetism-MCQs-2.jpg","articleSection":["Vegetables at home"],"inLanguage":"en-US"},{"@type":"WebPage","@id":"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/","url":"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/","name":"Physics: Electricity &amp; Magnetism MCQs - 2 - Johnson&#039;s TechNAgro","isPartOf":{"@id":"https:\/\/johnsonfrancis.org\/horticulture\/#website"},"primaryImageOfPage":{"@id":"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/#primaryimage"},"image":{"@id":"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/#primaryimage"},"thumbnailUrl":"https:\/\/johnsonfrancis.org\/horticulture\/wp-content\/uploads\/2026\/10\/Physics-Electricity-and-Magnetism-MCQs-2.jpg","datePublished":"2026-10-26T15:20:59+00:00","dateModified":"2026-10-26T15:31:56+00:00","breadcrumb":{"@id":"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/#primaryimage","url":"https:\/\/johnsonfrancis.org\/horticulture\/wp-content\/uploads\/2026\/10\/Physics-Electricity-and-Magnetism-MCQs-2.jpg","contentUrl":"https:\/\/johnsonfrancis.org\/horticulture\/wp-content\/uploads\/2026\/10\/Physics-Electricity-and-Magnetism-MCQs-2.jpg","width":1208,"height":675},{"@type":"BreadcrumbList","@id":"https:\/\/johnsonfrancis.org\/horticulture\/physics-electricity-magnetism-mcqs-2\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/johnsonfrancis.org\/horticulture\/"},{"@type":"ListItem","position":2,"name":"Physics: Electricity &amp; Magnetism MCQs &#8211; 2"}]},{"@type":"WebSite","@id":"https:\/\/johnsonfrancis.org\/horticulture\/#website","url":"https:\/\/johnsonfrancis.org\/horticulture\/","name":"Johnson's Horticulture","description":"Johnson&#039;s TechNAgro","publisher":{"@id":"https:\/\/johnsonfrancis.org\/horticulture\/#\/schema\/person\/c3636df643ae569b05229e17c67a85f1"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/johnsonfrancis.org\/horticulture\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":["Person","Organization"],"@id":"https:\/\/johnsonfrancis.org\/horticulture\/#\/schema\/person\/c3636df643ae569b05229e17c67a85f1","name":"Johnson Francis","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/johnsonfrancis.org\/horticulture\/#\/schema\/person\/image\/","url":"https:\/\/johnsonfrancis.org\/horticulture\/wp-content\/uploads\/2025\/01\/channels4_profile-1.jpg","contentUrl":"https:\/\/johnsonfrancis.org\/horticulture\/wp-content\/uploads\/2025\/01\/channels4_profile-1.jpg","width":600,"height":600,"caption":"Johnson Francis"},"logo":{"@id":"https:\/\/johnsonfrancis.org\/horticulture\/#\/schema\/person\/image\/"},"sameAs":["https:\/\/johnsonfrancis.org\/horticulture","https:\/\/www.youtube.com\/@JohnsonsHorticulture\/"],"url":"https:\/\/johnsonfrancis.org\/horticulture\/author\/jf\/"}]}},"_links":{"self":[{"href":"https:\/\/johnsonfrancis.org\/horticulture\/wp-json\/wp\/v2\/posts\/5475","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/johnsonfrancis.org\/horticulture\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/johnsonfrancis.org\/horticulture\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/johnsonfrancis.org\/horticulture\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/johnsonfrancis.org\/horticulture\/wp-json\/wp\/v2\/comments?post=5475"}],"version-history":[{"count":3,"href":"https:\/\/johnsonfrancis.org\/horticulture\/wp-json\/wp\/v2\/posts\/5475\/revisions"}],"predecessor-version":[{"id":5481,"href":"https:\/\/johnsonfrancis.org\/horticulture\/wp-json\/wp\/v2\/posts\/5475\/revisions\/5481"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/johnsonfrancis.org\/horticulture\/wp-json\/wp\/v2\/media\/5476"}],"wp:attachment":[{"href":"https:\/\/johnsonfrancis.org\/horticulture\/wp-json\/wp\/v2\/media?parent=5475"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/johnsonfrancis.org\/horticulture\/wp-json\/wp\/v2\/categories?post=5475"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/johnsonfrancis.org\/horticulture\/wp-json\/wp\/v2\/tags?post=5475"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}