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

[单选题]
The time for two eve tl5r o9a4hwvf-)b; 4d0 siqsbnts, a q-ufvq f2.o jo,;, qoplr/ x(j i(rh;aand 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 uncertainties. They cannot boibpz *+)-(u v hb5joyvq6enc8th be the smallest, so th8v b o65)ej uv+nphq(-zciby* ey 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 uncertainty of A is the smallest.