Kognity IB Physics A.0 Measurements & Uncertainty (id: 294aaa607)

[单选题]
The length of a pencil is mewd*7 a4 .wovep ;dae7vasured using part of 2 y*x a.xdyk 2m9fk;bk8v,r kja measuring tape as shown belowjkvkyxdxy;a ,f kr*2m k29b.8.

What is the length of the pencil?

A. $4.5 \pm 0.1 \; cm$
B. $11.5 \pm 0.2 \; cm$
C. $11.5 \pm 0.3 \; cm$
D. $11.5 \pm 0.5 \; cm$


参考答案:  D


本题详细解析:
We should be looking at the cm scale! The uncertainty in a reading on a scale i+w/0/ha6gy-zuwu qoke43q31 d. he xkdhnn )is usually taken as half the smallest division. Here the smallest division is 0.5 cm so we can read each point on the scale to an accuracy of 0.25 cm. To find the length of the pencil we must take two measurements - one for each end of the pencil. This means that we must also add the uncertaintie q e4 iqhy3k-o.dh3w+ 6n/ ukh0d)zua1gn/xwes, giving an uncertainty of 0.5cm.