问题 单项选择题 A1/A2型题

下列关于相对误差说法不正确的是()。

A.相对误差是一个百分数

B.相对误差没有度量衡单位

C.相对误差可以准确获知

D.多次测量相对误差不一定相等

E.相对误差更能反映测量的可信程度

答案

参考答案:C

解析:本题考点是相对误差定义。相对误差等于测量的绝对误差与被测量(约定)真值之比,再乘以100所得的数值,以百分数表示,即绝对误差在真实值中所占的百分率。两次测量的绝对误差相同而相对误差并不一定相同,因此说,相对误差更能反映测量的可信程度。由于测量值的真值是不可知的,因此其相对误差也是无法准确获知的,我们提到相对误差时,指的一般是相对误差限,即相对误差可能取得的最大值(上限)。

单项选择题

(B)

When first entered, Vanak Restaurant does not look like much of a restaurant, but once the pleasant smells of kabob(烤肉串)hit the senses, you are incapable of calling it anything less.

Owned by a local couple, this Persian restaurant has an inviting, homelike atmosphere that many restaurants lack.

The space is small with only a few dining tables and nearly no decoration, but the environment is truly charming.

Lying in a hardly noticeable steed corner, the restaurant still attracts all customers, especially those experienced in the delights of Middle Easter cooking.

A common sight is that of old Persian men sitting in the corner talking loudly about world topics, watching news events on TV, drinking a black tea known as Persian chai, and reading local Persian newspapers all the while trying to finish off their plates piled with food.

The variety of food at the restaurant is limited, but the amount of each dish is fairly large. Most of the meals can serve two people and are under $10, so not only is it affordable but practical as well.

The food especially appeals to health-conscious eaters because each dish is very healthy, made with limited fat and oil and served straight off the grill.

The main dish that the restaurant is popular for its kabobs, which are different styles of grilled meat.

One delicious and extremely healthy dish is the Joojeh Kabob, which is made of grilled chicken pieces served with either rice or bread. Another great kabob is the Chelo Kabob, a kabob consisting of grilled beef.

Although the restaurant is small, the atmosphere and the food is delicious. It is a place that should not be overlooked.

It can be inferred from the passage that the restaurant()

A. occupies a large space

B. owns a favorable location

C. is popular for its special food

D. has a quiet environment inside

单项选择题