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

[单选题]
The time for two everb6va)c ;mp b4 yx;-ns f rz9pk-p4ions:f5rop)nfx +u8l1; nnts, 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 identha*95 q1pgm xhl+lg nc a/:wp;ical fractional 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 to B a;+9 /g x*q5l1pnhg:lphmawc (0.2). Hence fractional uncertainty of A is the smallest.