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

[单选题]
The time for two events, a and b, are my -n4 *praj;kweasured to 6f xcvb7 1vlf9be $(5.1 \pm 0.1)s$ 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 fractional uncertainties. Theoz:f3j w42i+ v1jx/+x u ywowiy 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 to B (0.2). Hence fractional uncertainux+z1wow/ fj:4w 23x yvi+ijoty of A is the smallest.