Kognity IB Physics A.0 Measurements & Uncertainty (id: 3dae35a97)

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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]
A student measures two lengths l./ bqqe mqu+q/5 xw t/v/xire+za( i)as +1ovxffoo0 :hfollows: $$a = (10 \pm 0.1) \; cm$$ $$b = (20 \pm 0.1) \; cm$$
Which of the following quantities has the largest percentage uncertainty?

A. $a$
B. $b$
C. $a+b$
D. $a-b$


参考答案:  D


本题详细解析:
The largest percentage uncertainty will result from the larges4 e+ccrw*iu,d,eg. b:j)ogpy t absolute uncertainty divided by the smallest measurement value. A and B have an absolute uncertainty of 0.1 cm, while for C & D it is 0.2 cm. So the percentage uncertainties are: A 1%; ip)ge cu,d *rboe.yj4wc+g: ,B 0.5%; C 0.67%; and D 2%. Clearly D is the largest.