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<h2>SL Paper 1</h2><div class="question">
<p style="text-align:left;">Two charges, +Q and −Q, are placed as shown.</p>
<p style="text-align:left;">What is the magnitude of the electric field strength, in descending order, at points X, Y and Z.</p>
<p style="text-align:center;"><img src="data:image/png;base64,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"></p>
<p style="text-align:left;"> </p>
<p style="text-align:left;">A. YXZ</p>
<p style="text-align:left;">B. ZXY</p>
<p style="text-align:left;">C. ZYX</p>
<p style="text-align:left;">D. YZX</p>
</div>
<h2 style="margin-top: 1em">Markscheme</h2>
<div class="question">
<p>C</p>
</div>
<h2 style="margin-top: 1em">Examiners report</h2>
<div class="question">
<p>This question was well answered by candidates, with a high difficulty index.</p>
</div>
<br><hr><br>