本题目来源于试卷: Kognity IB Physics A.0 Measurements & Uncertainty，类别为 IB物理学
[单选题]
The length of a pencil is m mga-lzu 13fakn/.q: reasured using par dt7y.8ojl bb g,y)3 bq n2r:aut of a measuring tape as shown below. a7:udgbr3o.y) y8j,bbqt ln2 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 pj,60mg, (v lz e8h bouhj/re,in a reading on a scale is usually taken as half the smallest division. Here the smallest division is 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(,e, gh 6herljo/pm,u j vz08b we must also add the uncertainties, giving an uncertainty of 0.5cm.
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