Kognity IB Physics A.0 Measurements & Uncertainty (id: 294aaa607)

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本题目来源于试卷: Kognity IB Physics A.0 Measurements & Uncertainty，类别为 IBDP Physics

[单选题]
The length of a pencv.d/i)w(n 47bmeaxu1r b gul92j s*dq il z+y+va qwrrnrzpq g.+,7ev42m11l k du2gy8xis measured using part of a measuring tape as shown belowgrgmz w8 rk ,u+7 dy4yeaq121. z+vqn lv2r+px.

What is the length of the pencil?

A. $4.5 \pm 0.1 \; cm$
B. $11.5 \pm 0.2 \; cm$
C. $11.5 \pm 0.3 \; cm$
D. $11.5 \pm 0.5 \; cm$


参考答案:  D


本题详细解析:
We should be looking at the cm scale! The uncertainty in a reading on 2,cr5kd sgq dc.,0h.s2xhk 1jji q+cta scale is usually taken as half the smallest division. Here the smallest division i 1qjq0sjg.x ,sdhit2c5h2 cdr.+,k ck s 0.5 cm so we can read each point on the scale to an accuracy of 0.25 cm. To find the length of the pencil we must take two measurements - one for each end of the pencil. This means that we must also add the uncertainties, giving an uncertainty of 0.5cm.