<div class="xblock xblock-public_view xblock-public_view-vertical" data-request-token="afa38ccc075511f0a1fb0affe2bbc7c1" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@vertical+block@c7a78ac641974824b30a0552df30891d" data-init="VerticalStudentView" data-block-type="vertical" data-runtime-class="LmsRuntime" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="False" data-graded="False" data-runtime-version="1">
<h2 class="hd hd-2 unit-title">Transformers</h2>
<div class="vert-mod">
<div class="vert vert-0" data-id="block-v1:MITx+3.15.3x+2T2017+type@html+block@353fb5fd31f441df916244c17c82f8f3">
<div class="xblock xblock-public_view xblock-public_view-html xmodule_display xmodule_HtmlBlock" data-request-token="afa38ccc075511f0a1fb0affe2bbc7c1" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@html+block@353fb5fd31f441df916244c17c82f8f3" data-init="XBlockToXModuleShim" data-block-type="html" data-runtime-class="LmsRuntime" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="False" data-graded="False" data-runtime-version="1">
<script type="json/xblock-args" class="xblock-json-init-args">
{"xmodule-type": "HTMLModule"}
</script>
<h2>Transformers</h2>
<p>In a transformer, two coils are wrapped around a soft magnetic core.</p>
<p><img src="/assets/courseware/v1/dcc62181c46e0e33dcdd5b590512830d/asset-v1:MITx+3.15.3x+2T2017+type@asset+block/Graph10.jpg" alt="Illustration of transformer described below" type="saveimage" target="[object Object]" width="500" height="341" /></p>
<p>(1) The coil on the input side has a varying current \(i_m\) through \(n\) turns of wire.</p>
<ul>
<ul>
<ul>
<li>Ampere's law tells us that \(\oint Hdl = n i_m\)</li>
</ul>
</ul>
</ul>
<p><span style="line-height: 1.6;">(2) Within the core, \(B = \mu_0 \mu_r H\). </span></p>
<p>(3) Faraday's law tells us that a voltage will be induced in the second coil:</p>
<ul>
<ul>
<ul>
<li>\(V = -n^{\prime}\frac{d\phi}{ dt}\), where \(n^{\prime}\) is the number of turns in the secondary coil, and \(\phi = BA\), where \(A\) is the coil area.</li>
</ul>
</ul>
</ul>
<p><span style="line-height: 1.6;">(3) We draw current \(i_s\) from the secondary coil. The current \(i_s\) induces a current \(i_p\) in the primary current. The primary current is now im + ip, i.e. the power supply attached to the primary side now has to supply a larger amount of current (and therefore power) when power is taken from the secondary side.</span></p>
<ul>
<ul>
<ul>
<li>\(\frac{V_s}{ i_p} = \frac{V_p}{ i_s}\), where \(\frac{V_s}{V_p} = \frac{n^{\prime}}{n}\)</li>
</ul>
</ul>
</ul>
<p>(4) The magnetic core of the transistor requires the following properties:</p>
<ul>
<ul>
<ul>
<li>easy to magnetize (high permeability)</li>
<li>high \(B_s\)</li>
<li>low hysteresis</li>
<li>resistive to avoid eddy currents</li>
</ul>
</ul>
</ul>
</div>
</div>
<div class="vert vert-1" data-id="block-v1:MITx+3.15.3x+2T2017+type@problem+block@d771cb4948b74a64b2a2b2ef37e026a2">
<div class="xblock xblock-public_view xblock-public_view-problem xmodule_display xmodule_ProblemBlock" data-request-token="afa38ccc075511f0a1fb0affe2bbc7c1" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@problem+block@d771cb4948b74a64b2a2b2ef37e026a2" data-init="XBlockToXModuleShim" data-block-type="problem" data-runtime-class="LmsRuntime" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="True" data-graded="False" data-runtime-version="1">
<script type="json/xblock-args" class="xblock-json-init-args">
{"xmodule-type": "Problem"}
</script>
<div id="problem_d771cb4948b74a64b2a2b2ef37e026a2" class="problems-wrapper" role="group"
aria-labelledby="d771cb4948b74a64b2a2b2ef37e026a2-problem-title"
data-problem-id="block-v1:MITx+3.15.3x+2T2017+type@problem+block@d771cb4948b74a64b2a2b2ef37e026a2" data-url="/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@problem+block@d771cb4948b74a64b2a2b2ef37e026a2/handler/xmodule_handler"
data-problem-score="0"
data-problem-total-possible="1"
data-attempts-used="0"
data-content="
<h3 class="hd hd-3 problem-header" id="d771cb4948b74a64b2a2b2ef37e026a2-problem-title" aria-describedby="block-v1:MITx+3.15.3x+2T2017+type@problem+block@d771cb4948b74a64b2a2b2ef37e026a2-problem-progress" tabindex="-1">
Example 2.1A
</h3>
<div class="problem-progress" id="block-v1:MITx+3.15.3x+2T2017+type@problem+block@d771cb4948b74a64b2a2b2ef37e026a2-problem-progress"></div>
<div class="problem">
<div>
<p>A transformer connected to a \(120\; V\) power source supplies \(5V\) to a device. If the primary coil has \(96\) turns, how many turns should the secondary coil need?</p>
<p>\(n\) (number of turns):</p>
<div class="wrapper-problem-response" tabindex="-1" aria-label="Question 1" role="group"><div id="formulaequationinput_d771cb4948b74a64b2a2b2ef37e026a2_2_1" class="inputtype formulaequationinput">
<div class="unanswered">
<input type="text" name="input_d771cb4948b74a64b2a2b2ef37e026a2_2_1" id="input_d771cb4948b74a64b2a2b2ef37e026a2_2_1" data-input-id="d771cb4948b74a64b2a2b2ef37e026a2_2_1" value="" aria-describedby="status_d771cb4948b74a64b2a2b2ef37e026a2_2_1" size="20"/>
<span class="trailing_text" id="trailing_text_d771cb4948b74a64b2a2b2ef37e026a2_2_1"/>
<span class="status unanswered" id="status_d771cb4948b74a64b2a2b2ef37e026a2_2_1" data-tooltip="Not yet answered.">
<span class="sr">unanswered</span><span class="status-icon" aria-hidden="true"/>
</span>
<p id="answer_d771cb4948b74a64b2a2b2ef37e026a2_2_1" class="answer"/>
<div id="input_d771cb4948b74a64b2a2b2ef37e026a2_2_1_preview" class="equation">
\(\)
<img src="/static/images/spinner.bc34f953403f.gif" class="loading" alt="Loading"/>
</div>
</div>
<div class="script_placeholder" data-src="/static/js/capa/src/formula_equation_preview.b1967ab28c31.js"/>
</div></div>
<div class="solution-span">
<span id="solution_d771cb4948b74a64b2a2b2ef37e026a2_solution_1"/>
</div></div>
<div class="action">
<input type="hidden" name="problem_id" value="Example 2.1A" />
<div class="submit-attempt-container">
<button type="button" class="submit btn-brand" data-submitting="Submitting" data-value="Submit" data-should-enable-submit-button="True" aria-describedby="submission_feedback_d771cb4948b74a64b2a2b2ef37e026a2" >
<span class="submit-label">Submit</span>
</button>
<div class="submission-feedback" id="submission_feedback_d771cb4948b74a64b2a2b2ef37e026a2">
<span class="sr">Some problems have options such as save, reset, hints, or show answer. These options follow the Submit button.</span>
</div>
</div>
<div class="problem-action-buttons-wrapper">
</div>
</div>
<div class="notification warning notification-gentle-alert
is-hidden"
tabindex="-1">
<span class="icon fa fa-exclamation-circle" aria-hidden="true"></span>
<span class="notification-message" aria-describedby="d771cb4948b74a64b2a2b2ef37e026a2-problem-title">
</span>
<div class="notification-btn-wrapper">
<button type="button" class="btn btn-default btn-small notification-btn review-btn sr">Review</button>
</div>
</div>
<div class="notification warning notification-save
is-hidden"
tabindex="-1">
<span class="icon fa fa-save" aria-hidden="true"></span>
<span class="notification-message" aria-describedby="d771cb4948b74a64b2a2b2ef37e026a2-problem-title">None
</span>
<div class="notification-btn-wrapper">
<button type="button" class="btn btn-default btn-small notification-btn review-btn sr">Review</button>
</div>
</div>
<div class="notification general notification-show-answer
is-hidden"
tabindex="-1">
<span class="icon fa fa-info-circle" aria-hidden="true"></span>
<span class="notification-message" aria-describedby="d771cb4948b74a64b2a2b2ef37e026a2-problem-title">Answers are displayed within the problem
</span>
<div class="notification-btn-wrapper">
<button type="button" class="btn btn-default btn-small notification-btn review-btn sr">Review</button>
</div>
</div>
</div>
"
data-graded="False">
<p class="loading-spinner">
<i class="fa fa-spinner fa-pulse fa-2x fa-fw"></i>
<span class="sr">Loading…</span>
</p>
</div>
</div>
</div>
<div class="vert vert-2" data-id="block-v1:MITx+3.15.3x+2T2017+type@problem+block@d43af13fc6d84061bb52065d98004c53">
<div class="xblock xblock-public_view xblock-public_view-problem xmodule_display xmodule_ProblemBlock" data-request-token="afa38ccc075511f0a1fb0affe2bbc7c1" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@problem+block@d43af13fc6d84061bb52065d98004c53" data-init="XBlockToXModuleShim" data-block-type="problem" data-runtime-class="LmsRuntime" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="True" data-graded="False" data-runtime-version="1">
<script type="json/xblock-args" class="xblock-json-init-args">
{"xmodule-type": "Problem"}
</script>
<div id="problem_d43af13fc6d84061bb52065d98004c53" class="problems-wrapper" role="group"
aria-labelledby="d43af13fc6d84061bb52065d98004c53-problem-title"
data-problem-id="block-v1:MITx+3.15.3x+2T2017+type@problem+block@d43af13fc6d84061bb52065d98004c53" data-url="/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@problem+block@d43af13fc6d84061bb52065d98004c53/handler/xmodule_handler"
data-problem-score="0"
data-problem-total-possible="1"
data-attempts-used="0"
data-content="
<h3 class="hd hd-3 problem-header" id="d43af13fc6d84061bb52065d98004c53-problem-title" aria-describedby="block-v1:MITx+3.15.3x+2T2017+type@problem+block@d43af13fc6d84061bb52065d98004c53-problem-progress" tabindex="-1">
Example 2.1B
</h3>
<div class="problem-progress" id="block-v1:MITx+3.15.3x+2T2017+type@problem+block@d43af13fc6d84061bb52065d98004c53-problem-progress"></div>
<div class="problem">
<div>
<p>If we draw \(0.5 \;A\) from the secondary coil, what is the current in the primary coil?</p>
<p>\(i_p\) (in \(A\)):</p>
<div class="wrapper-problem-response" tabindex="-1" aria-label="Question 1" role="group"><div id="formulaequationinput_d43af13fc6d84061bb52065d98004c53_2_1" class="inputtype formulaequationinput">
<div class="unanswered">
<input type="text" name="input_d43af13fc6d84061bb52065d98004c53_2_1" id="input_d43af13fc6d84061bb52065d98004c53_2_1" data-input-id="d43af13fc6d84061bb52065d98004c53_2_1" value="" aria-describedby="status_d43af13fc6d84061bb52065d98004c53_2_1" size="20"/>
<span class="trailing_text" id="trailing_text_d43af13fc6d84061bb52065d98004c53_2_1"/>
<span class="status unanswered" id="status_d43af13fc6d84061bb52065d98004c53_2_1" data-tooltip="Not yet answered.">
<span class="sr">unanswered</span><span class="status-icon" aria-hidden="true"/>
</span>
<p id="answer_d43af13fc6d84061bb52065d98004c53_2_1" class="answer"/>
<div id="input_d43af13fc6d84061bb52065d98004c53_2_1_preview" class="equation">
\(\)
<img src="/static/images/spinner.bc34f953403f.gif" class="loading" alt="Loading"/>
</div>
</div>
<div class="script_placeholder" data-src="/static/js/capa/src/formula_equation_preview.b1967ab28c31.js"/>
</div></div>
<div class="solution-span">
<span id="solution_d43af13fc6d84061bb52065d98004c53_solution_1"/>
</div></div>
<div class="action">
<input type="hidden" name="problem_id" value="Example 2.1B" />
<div class="submit-attempt-container">
<button type="button" class="submit btn-brand" data-submitting="Submitting" data-value="Submit" data-should-enable-submit-button="True" aria-describedby="submission_feedback_d43af13fc6d84061bb52065d98004c53" >
<span class="submit-label">Submit</span>
</button>
<div class="submission-feedback" id="submission_feedback_d43af13fc6d84061bb52065d98004c53">
<span class="sr">Some problems have options such as save, reset, hints, or show answer. These options follow the Submit button.</span>
</div>
</div>
<div class="problem-action-buttons-wrapper">
</div>
</div>
<div class="notification warning notification-gentle-alert
is-hidden"
tabindex="-1">
<span class="icon fa fa-exclamation-circle" aria-hidden="true"></span>
<span class="notification-message" aria-describedby="d43af13fc6d84061bb52065d98004c53-problem-title">
</span>
<div class="notification-btn-wrapper">
<button type="button" class="btn btn-default btn-small notification-btn review-btn sr">Review</button>
</div>
</div>
<div class="notification warning notification-save
is-hidden"
tabindex="-1">
<span class="icon fa fa-save" aria-hidden="true"></span>
<span class="notification-message" aria-describedby="d43af13fc6d84061bb52065d98004c53-problem-title">None
</span>
<div class="notification-btn-wrapper">
<button type="button" class="btn btn-default btn-small notification-btn review-btn sr">Review</button>
</div>
</div>
<div class="notification general notification-show-answer
is-hidden"
tabindex="-1">
<span class="icon fa fa-info-circle" aria-hidden="true"></span>
<span class="notification-message" aria-describedby="d43af13fc6d84061bb52065d98004c53-problem-title">Answers are displayed within the problem
</span>
<div class="notification-btn-wrapper">
<button type="button" class="btn btn-default btn-small notification-btn review-btn sr">Review</button>
</div>
</div>
</div>
"
data-graded="False">
<p class="loading-spinner">
<i class="fa fa-spinner fa-pulse fa-2x fa-fw"></i>
<span class="sr">Loading…</span>
</p>
</div>
</div>
</div>
</div>
</div>
<div class="xblock xblock-public_view xblock-public_view-vertical" data-request-token="afa38ccc075511f0a1fb0affe2bbc7c1" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@vertical+block@796a8e83766c417cb1a4295569715855" data-init="VerticalStudentView" data-block-type="vertical" data-runtime-class="LmsRuntime" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="False" data-graded="False" data-runtime-version="1">
<h2 class="hd hd-2 unit-title">DC Motors</h2>
<div class="vert-mod">
<div class="vert vert-0" data-id="block-v1:MITx+3.15.3x+2T2017+type@html+block@725660b0803842c590c5c71acec08c08">
<div class="xblock xblock-public_view xblock-public_view-html xmodule_display xmodule_HtmlBlock" data-request-token="afa38ccc075511f0a1fb0affe2bbc7c1" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@html+block@725660b0803842c590c5c71acec08c08" data-init="XBlockToXModuleShim" data-block-type="html" data-runtime-class="LmsRuntime" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="False" data-graded="False" data-runtime-version="1">
<script type="json/xblock-args" class="xblock-json-init-args">
{"xmodule-type": "HTMLModule"}
</script>
<h2>DC Motors</h2>
<p>(1) DC Motors employ a permanent magnet. The field produced by the magnet exerts a force \(F\) on a current-carrying wire, which is given as follows:</p>
<ul>
<ul>
<ul>
<li>\(F = Bil\), where \(i\) is the current running through the wire, and \(l\) is the length of the wire. </li>
<li>The direction of the force is given by Fleming's Left Hand Rule, which tells us that the force \(F\) is perpendicular to both \(B\) and \(i\).</li>
</ul>
</ul>
</ul>
<p>(2) For a magnet to be able to do work, it needs to produce an external flux. Consider the gap of a ring-shaped magnet with a cut made in it. A field \(H_g\) exists in the gap.</p>
<p><img src="/assets/courseware/v1/942c20befc41c43a321b6514290457aa/asset-v1:MITx+3.15.3x+2T2017+type@asset+block/315_DC_Motor_Magnet.jpg" alt="Circular magnet with small gap" type="saveimage" target="[object Object]" width="300" height="224" /></p>
<p>(3) From Ampere's law, we know:</p>
<ul>
<ul>
<ul>
<li>\(l_mH_m + l_gH_g = 0\) around the dotted line</li>
<li>also, \(B_m = B_g\)</li>
<li>alternatively, \(B_m = \mu_0 \mu_r H_m\)</li>
<li>\(B_g = \mu_0 H_g\)</li>
<li>therefore, \(H_m = \frac{-l_g B_m}{l_m \mu_0}\)</li>
</ul>
</ul>
</ul>
<p></p>
</div>
</div>
<div class="vert vert-1" data-id="block-v1:MITx+3.15.3x+2T2017+type@problem+block@af9e1ca046c445caa47b2f39df4c669e">
<div class="xblock xblock-public_view xblock-public_view-problem xmodule_display xmodule_ProblemBlock" data-request-token="afa38ccc075511f0a1fb0affe2bbc7c1" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@problem+block@af9e1ca046c445caa47b2f39df4c669e" data-init="XBlockToXModuleShim" data-block-type="problem" data-runtime-class="LmsRuntime" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="True" data-graded="False" data-runtime-version="1">
<script type="json/xblock-args" class="xblock-json-init-args">
{"xmodule-type": "Problem"}
</script>
<div id="problem_af9e1ca046c445caa47b2f39df4c669e" class="problems-wrapper" role="group"
aria-labelledby="af9e1ca046c445caa47b2f39df4c669e-problem-title"
data-problem-id="block-v1:MITx+3.15.3x+2T2017+type@problem+block@af9e1ca046c445caa47b2f39df4c669e" data-url="/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@problem+block@af9e1ca046c445caa47b2f39df4c669e/handler/xmodule_handler"
data-problem-score="0"
data-problem-total-possible="1"
data-attempts-used="0"
data-content="
<h3 class="hd hd-3 problem-header" id="af9e1ca046c445caa47b2f39df4c669e-problem-title" aria-describedby="block-v1:MITx+3.15.3x+2T2017+type@problem+block@af9e1ca046c445caa47b2f39df4c669e-problem-progress" tabindex="-1">
Example 2.2A
</h3>
<div class="problem-progress" id="block-v1:MITx+3.15.3x+2T2017+type@problem+block@af9e1ca046c445caa47b2f39df4c669e-problem-progress"></div>
<div class="problem">
<div>
<p>The core of our DC motor is made out of iron, with a \(\mu_r = 5000\) and a saturation induction \(B_{sat} = 2\;T\)</p>
<p>At saturation, what is the magnetic flux density \(B_{gap}\) in the gap?</p>
<p>\(B_{gap}\) (in \(T\)):</p>
<div class="wrapper-problem-response" tabindex="-1" aria-label="Question 1" role="group"><div id="formulaequationinput_af9e1ca046c445caa47b2f39df4c669e_2_1" class="inputtype formulaequationinput">
<div class="unanswered">
<input type="text" name="input_af9e1ca046c445caa47b2f39df4c669e_2_1" id="input_af9e1ca046c445caa47b2f39df4c669e_2_1" data-input-id="af9e1ca046c445caa47b2f39df4c669e_2_1" value="" aria-describedby="status_af9e1ca046c445caa47b2f39df4c669e_2_1" size="20"/>
<span class="trailing_text" id="trailing_text_af9e1ca046c445caa47b2f39df4c669e_2_1"/>
<span class="status unanswered" id="status_af9e1ca046c445caa47b2f39df4c669e_2_1" data-tooltip="Not yet answered.">
<span class="sr">unanswered</span><span class="status-icon" aria-hidden="true"/>
</span>
<p id="answer_af9e1ca046c445caa47b2f39df4c669e_2_1" class="answer"/>
<div id="input_af9e1ca046c445caa47b2f39df4c669e_2_1_preview" class="equation">
\(\)
<img src="/static/images/spinner.bc34f953403f.gif" class="loading" alt="Loading"/>
</div>
</div>
<div class="script_placeholder" data-src="/static/js/capa/src/formula_equation_preview.b1967ab28c31.js"/>
</div></div>
<div class="solution-span">
<span id="solution_af9e1ca046c445caa47b2f39df4c669e_solution_1"/>
</div></div>
<div class="action">
<input type="hidden" name="problem_id" value="Example 2.2A" />
<div class="submit-attempt-container">
<button type="button" class="submit btn-brand" data-submitting="Submitting" data-value="Submit" data-should-enable-submit-button="True" aria-describedby="submission_feedback_af9e1ca046c445caa47b2f39df4c669e" >
<span class="submit-label">Submit</span>
</button>
<div class="submission-feedback" id="submission_feedback_af9e1ca046c445caa47b2f39df4c669e">
<span class="sr">Some problems have options such as save, reset, hints, or show answer. These options follow the Submit button.</span>
</div>
</div>
<div class="problem-action-buttons-wrapper">
</div>
</div>
<div class="notification warning notification-gentle-alert
is-hidden"
tabindex="-1">
<span class="icon fa fa-exclamation-circle" aria-hidden="true"></span>
<span class="notification-message" aria-describedby="af9e1ca046c445caa47b2f39df4c669e-problem-title">
</span>
<div class="notification-btn-wrapper">
<button type="button" class="btn btn-default btn-small notification-btn review-btn sr">Review</button>
</div>
</div>
<div class="notification warning notification-save
is-hidden"
tabindex="-1">
<span class="icon fa fa-save" aria-hidden="true"></span>
<span class="notification-message" aria-describedby="af9e1ca046c445caa47b2f39df4c669e-problem-title">None
</span>
<div class="notification-btn-wrapper">
<button type="button" class="btn btn-default btn-small notification-btn review-btn sr">Review</button>
</div>
</div>
<div class="notification general notification-show-answer
is-hidden"
tabindex="-1">
<span class="icon fa fa-info-circle" aria-hidden="true"></span>
<span class="notification-message" aria-describedby="af9e1ca046c445caa47b2f39df4c669e-problem-title">Answers are displayed within the problem
</span>
<div class="notification-btn-wrapper">
<button type="button" class="btn btn-default btn-small notification-btn review-btn sr">Review</button>
</div>
</div>
</div>
"
data-graded="False">
<p class="loading-spinner">
<i class="fa fa-spinner fa-pulse fa-2x fa-fw"></i>
<span class="sr">Loading…</span>
</p>
</div>
</div>
</div>
<div class="vert vert-2" data-id="block-v1:MITx+3.15.3x+2T2017+type@problem+block@33c72d37566040e79c35b62935166f31">
<div class="xblock xblock-public_view xblock-public_view-problem xmodule_display xmodule_ProblemBlock" data-request-token="afa38ccc075511f0a1fb0affe2bbc7c1" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@problem+block@33c72d37566040e79c35b62935166f31" data-init="XBlockToXModuleShim" data-block-type="problem" data-runtime-class="LmsRuntime" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="True" data-graded="False" data-runtime-version="1">
<script type="json/xblock-args" class="xblock-json-init-args">
{"xmodule-type": "Problem"}
</script>
<div id="problem_33c72d37566040e79c35b62935166f31" class="problems-wrapper" role="group"
aria-labelledby="33c72d37566040e79c35b62935166f31-problem-title"
data-problem-id="block-v1:MITx+3.15.3x+2T2017+type@problem+block@33c72d37566040e79c35b62935166f31" data-url="/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@problem+block@33c72d37566040e79c35b62935166f31/handler/xmodule_handler"
data-problem-score="0"
data-problem-total-possible="1"
data-attempts-used="0"
data-content="
<h3 class="hd hd-3 problem-header" id="33c72d37566040e79c35b62935166f31-problem-title" aria-describedby="block-v1:MITx+3.15.3x+2T2017+type@problem+block@33c72d37566040e79c35b62935166f31-problem-progress" tabindex="-1">
Exercise 2.2B
</h3>
<div class="problem-progress" id="block-v1:MITx+3.15.3x+2T2017+type@problem+block@33c72d37566040e79c35b62935166f31-problem-progress"></div>
<div class="problem">
<div>
<p>What is the maximum field \(H_{gap}\) in the gap?</p>
<p>\(H_{gap}\) (in \(A/m\)):</p>
<div class="wrapper-problem-response" tabindex="-1" aria-label="Question 1" role="group"><div id="formulaequationinput_33c72d37566040e79c35b62935166f31_2_1" class="inputtype formulaequationinput">
<div class="unanswered">
<input type="text" name="input_33c72d37566040e79c35b62935166f31_2_1" id="input_33c72d37566040e79c35b62935166f31_2_1" data-input-id="33c72d37566040e79c35b62935166f31_2_1" value="" aria-describedby="status_33c72d37566040e79c35b62935166f31_2_1" size="20"/>
<span class="trailing_text" id="trailing_text_33c72d37566040e79c35b62935166f31_2_1"/>
<span class="status unanswered" id="status_33c72d37566040e79c35b62935166f31_2_1" data-tooltip="Not yet answered.">
<span class="sr">unanswered</span><span class="status-icon" aria-hidden="true"/>
</span>
<p id="answer_33c72d37566040e79c35b62935166f31_2_1" class="answer"/>
<div id="input_33c72d37566040e79c35b62935166f31_2_1_preview" class="equation">
\(\)
<img src="/static/images/spinner.bc34f953403f.gif" class="loading" alt="Loading"/>
</div>
</div>
<div class="script_placeholder" data-src="/static/js/capa/src/formula_equation_preview.b1967ab28c31.js"/>
</div></div>
<div class="solution-span">
<span id="solution_33c72d37566040e79c35b62935166f31_solution_1"/>
</div></div>
<div class="action">
<input type="hidden" name="problem_id" value="Exercise 2.2B" />
<div class="submit-attempt-container">
<button type="button" class="submit btn-brand" data-submitting="Submitting" data-value="Submit" data-should-enable-submit-button="True" aria-describedby="submission_feedback_33c72d37566040e79c35b62935166f31" >
<span class="submit-label">Submit</span>
</button>
<div class="submission-feedback" id="submission_feedback_33c72d37566040e79c35b62935166f31">
<span class="sr">Some problems have options such as save, reset, hints, or show answer. These options follow the Submit button.</span>
</div>
</div>
<div class="problem-action-buttons-wrapper">
</div>
</div>
<div class="notification warning notification-gentle-alert
is-hidden"
tabindex="-1">
<span class="icon fa fa-exclamation-circle" aria-hidden="true"></span>
<span class="notification-message" aria-describedby="33c72d37566040e79c35b62935166f31-problem-title">
</span>
<div class="notification-btn-wrapper">
<button type="button" class="btn btn-default btn-small notification-btn review-btn sr">Review</button>
</div>
</div>
<div class="notification warning notification-save
is-hidden"
tabindex="-1">
<span class="icon fa fa-save" aria-hidden="true"></span>
<span class="notification-message" aria-describedby="33c72d37566040e79c35b62935166f31-problem-title">None
</span>
<div class="notification-btn-wrapper">
<button type="button" class="btn btn-default btn-small notification-btn review-btn sr">Review</button>
</div>
</div>
<div class="notification general notification-show-answer
is-hidden"
tabindex="-1">
<span class="icon fa fa-info-circle" aria-hidden="true"></span>
<span class="notification-message" aria-describedby="33c72d37566040e79c35b62935166f31-problem-title">Answers are displayed within the problem
</span>
<div class="notification-btn-wrapper">
<button type="button" class="btn btn-default btn-small notification-btn review-btn sr">Review</button>
</div>
</div>
</div>
"
data-graded="False">
<p class="loading-spinner">
<i class="fa fa-spinner fa-pulse fa-2x fa-fw"></i>
<span class="sr">Loading…</span>
</p>
</div>
</div>
</div>
</div>
</div>
<div class="xblock xblock-public_view xblock-public_view-vertical" data-request-token="afa38ccc075511f0a1fb0affe2bbc7c1" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@vertical+block@476234786b7e49a594b0b577732e40ef" data-init="VerticalStudentView" data-block-type="vertical" data-runtime-class="LmsRuntime" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="False" data-graded="False" data-runtime-version="1">
<h2 class="hd hd-2 unit-title">Magnetic Data Storage</h2>
<div class="vert-mod">
<div class="vert vert-0" data-id="block-v1:MITx+3.15.3x+2T2017+type@drag-and-drop-v2+block@7d7305f6600143e7983fb3d84cea564b">
<div class="xblock xblock-public_view xblock-public_view-drag-and-drop-v2" data-request-token="afa38ccc075511f0a1fb0affe2bbc7c1" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@drag-and-drop-v2+block@7d7305f6600143e7983fb3d84cea564b" data-init="DragAndDropBlock" data-block-type="drag-and-drop-v2" data-runtime-class="LmsRuntime" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="True" data-graded="False" data-runtime-version="1">
<script type="json/xblock-args" class="xblock-json-init-args">
{"show_title": true, "display_name": "Exercise 2.3A", "has_deadline_passed": false, "target_img_description": "Two boxes, next to each other", "item_text_color": null, "max_items_per_zone": null, "show_problem_header": true, "is_anonymous_user": true, "display_zone_labels": false, "display_zone_borders": false, "zones": [{"y": "85", "description": "Use this zone to associate an item with the longitudinal magnetic recording", "height": "1125", "x": "79", "title": "Longitudinal Magnetic Recording", "uid": "top", "width": "795", "align": "center"}, {"y": "85", "description": "Use this zone to associate an item with perpendicular magnetic recording", "height": "1125", "x": "1160", "title": "Perpendicular Magnetic Recording", "uid": "middle", "width": "795", "align": "center"}], "item_background_color": null, "graded": false, "weight": 1.0, "max_attempts": 0, "items": [{"imageDescription": "", "expandedImageURL": "", "displayName": "Capable of higher-density recording", "id": 0, "imageURL": ""}, {"imageDescription": "", "expandedImageURL": "", "displayName": "Has mostly been replaced in modern media", "id": 1, "imageURL": ""}, {"imageDescription": "", "expandedImageURL": "", "displayName": "Magnetic layer consists of small grains of Co-alloy with in-plane c-axis", "id": 2, "imageURL": ""}, {"imageDescription": "", "expandedImageURL": "", "displayName": "Magnetization is oriented in the film plane, left to right", "id": 3, "imageURL": ""}, {"imageDescription": "", "expandedImageURL": "", "displayName": "Magnetization points up and down", "id": 4, "imageURL": ""}, {"imageDescription": "", "expandedImageURL": "", "displayName": "Media requires a soft magnetic underlayer", "id": 5, "imageURL": ""}, {"imageDescription": "", "expandedImageURL": "", "displayName": "Seed layer of Ti orients the easy axis of Co-alloy out of plane", "id": 6, "imageURL": ""}], "title": "Exercise 2.3A", "weighted_max_score": 1.0, "problem_text": "Review the lectures on longitudinal and perpendicular magnetic recording. Then sort the following statements, indicating whether they apply to longitudinal magnetic recording or to perpendicular magnetic recording.", "target_img_expanded_url": "/assets/courseware/v1/abc23426e2e76e4d483178dea42abb5e/asset-v1:MITx+3.15.3x+2T2017+type@asset+block/SortingBoxes2.jpg", "block_id": "block-v1:MITx+3.15.3x+2T2017+type@drag-and-drop-v2+block@7d7305f6600143e7983fb3d84cea564b", "mode": "standard", "url_name": "7d7305f6600143e7983fb3d84cea564b", "type": "drag-and-drop-v2"}
</script>
<div class="themed-xblock xblock--drag-and-drop">
<span class="fa fa-spin fa-spinner initial-load-spinner" aria-hidden="true"></span>
Loading drag and drop problem.
</div>
</div>
</div>
</div>
</div>
© All Rights Reserved