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

[单选题]
The time for two events, a and b, are mea(iawsi1bg v ;n (5-lys;lpa s:su0q-dp n-slbz5,aaueux l 793 8pz 6owhred 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 identical fra0e*)tvgeoycw 5j5 /** g bvei0 kxj-yfctional uncertainties. They cannot both be the smallest, so they must both be incorrect. A and B will have the same absolute uncertainty (0.2 s), but A is a large number (10) compared t o y0* kge05 bc)g/jvjyf *t-xv*eie5wo B (0.2). Hence fractional uncertainty of A is the smallest.