Kognity IB Physics A.0 Measurements & Uncertainty (id: 3dae35a97)

[单选题]
A student measures two lengtx1.mo+dc k0xn q;.f,bupnu.phs as foll;8hb(nl7h. ukwmu d7q6 r jw7uows: $$a = (10 \pm 0.1) \; cm$$ $$b = (20 \pm 0.1) \; cm$$
Which of the following quantities has the largest percentage uncertainty?

A. $a$
B. $b$
C. $a+b$
D. $a-b$


参考答案:  D


本题详细解析:
The largest percentage uncertainty will result from the q kk+p52l.gpcjxds*)v *8a e w2*hl wllargest absolute uncertainty divided by the smallest measurement value. A and B have an absolute uncertainty of 0.1 cm, while for C & D it is 0.2 cm. So the percentage uncertaintelpgqlw*k2a2svhk)* 8j wl.xd c+ p*5ies are: A 1%; B 0.5%; C 0.67%; and D 2%. Clearly D is the largest.