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 tw 1d0 dzzfqb;c7o let j) 3z ppaf *,x7kr+pn3kn6ntngths as follows: $$a = (10 \pm 0.1) \; cm$$ $$b = (20 \pm 0.1) \; cm$$
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 kj /3w*nt jtd pm8/2cpk t*;nkiv,.gzfrom the largest 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%; B 0.5%; C 0.67%; and D 2%. C t/n2p/wk3*ipc8.d v zn jtkm,tj*g ;klearly D is the largest.