Kognity IB Physics A.0 Measurements & Uncertainty (id: d206553aa)

[单选题]
The time for two events, a and b, are measure;vgl j,faq. f;*utj 1ed to belicl /gi ).sf/+fsl00mw3:q5 x dsj hz $(5.1 \pm 0.1)s$ and $(4.9 \pm 0.1)s$ respectively. In which of the following quantities is the fractional(percent) uncertainty the smallest?

A. $a+b$
B. $a-b$
C. $a \times b$
D. $a/b$


参考答案:  A


本题详细解析:
C and D will both have iz(silt5j vz28t efe, 7dentical fractional uncertainties. They cannot both be the smallest, so they must both beetj,lvf7e(2st58z i z incorrect. A and B will have the same absolute uncertainty (0.2 s), but A is a large number (10) compared to B (0.2). Hence fractional uncertainty of A is the smallest.