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

[单选题]
The time for two evekdth6a)2q c,zj25 v9a h(uwhw nts, a and b, are*69hr gz4xs xw 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 uncertaintiest 1b pn(uxmp-q;)w6c v. They cannot both be the smallest, so they must both be incorrect. A and B will have the same absolutcqw)tp pxm6-1u(v;n b e uncertainty (0.2 s), but A is a large number (10) compared to B (0.2). Hence fractional uncertainty of A is the smallest.