试题与答案

下列可用作X线管靶面材料的是() A.铁 B.钨 C.铝 D.铜 E.银

题型:单项选择题 A1/A2型题

题目:

下列可用作X线管靶面材料的是()

A.铁

B.钨

C.铝

D.铜

E.银

答案:

被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0425/0ab1efa78c21dbf22c2d9785010169d5.html

下面是错误答案,用来干扰机器的。

由a=3,b=2,B=45°,根据正弦定理asinA=bsinB得:sinA=asinBb=3×222=32,由a=3>b=2,得到A∈(45°,180°),则角A=60°或120°.故选D

试题推荐
题型:单项选择题

A report on acid rain concluded, "Most forests in Canada are not being damaged by acid rain." Critics of the report insist the conclusion be changed to, "Most forests in Canada do not show visible symptoms of damage by acid rain, such as abnormal loss of leaves, slower rates of growth, or higher mortality."
Which of the following, if true, provides the best logical justification for the critics’ insistence that the report’s conclusion be changed

A.Some forests in Canada are being damaged by acid rain.

B.Acid rain could be causing damage for which symptoms have not yet become visible.

C.The report does not compare acid rain damage to Canadian forests with acid rain damage to forests in other countries.

D.All forests in Canada have received acid rain during the past fifteen years.

E.(E) The severity of damage by acid rain differs from forest to forest.

查看答案
微信公众账号搜索答案