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

[单选题]
The time for two events,pi 41se /hh4:tabto:c zxt4i7 a ad64l j;0 iewac0i xgvh65 jt7t-emx.k nd 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 unc jq:w 72vgxwn(ertainties. They cannot both be the smallest, so they must both be incorrect.2(xvg jw:q nw7 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.