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

[单选题]
The time for two events, a cj3yw: cs.z:gia5k z2and b, are mii*f zq:qo (u)j lz0j4q3w, yoew mo.3easured to be $(5.1 \pm 0.1)s$ 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 identidcltx qcz: 4x.- (+uadvk)*dtcal fractional uncertainties. They cannot both be the smallest, so they must both be incorrect. A and B will lz)ddvt:c4 xc*.qtd- +kxu(a 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.