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

[单选题]
The time for two events,/hakkt/h5j (h ./i r()d3u0 ;chxdc 8t ydeosmei)v7h a and b, are measured 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 fractional unc4hgg f5u1c*yu 7i ;id6 (txm68r mmnwkertainties. They cannot both be the smallest, so they must bothm(8ghmxtk 16u4 *nwdri5iuy6fc ;7mg 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 uncertainty of A is the smallest.