一单色光垂直照射在空气劈尖上,当劈尖的劈角增大时,各级干涉条纹将有下列中的何种变化?

题型:单项选择题

问题:

一单色光垂直照射在空气劈尖上,当劈尖的劈角增大时,各级干涉条纹将有下列中的何种变化?()

A.向右移,且条纹的间距变大

B.向右移,且条纹的间距变小

C.向左移,且条纹的间距变小

D.向左移,且条纹的间距变大

考点:岩土工程基础知识第二章普通物理第二章普通物理题库
题型:单项选择题

某种商品在两个月内降价两次,现在该商品每件的价格比两个月前下降了36%,问

平均每月降价百分之几?设平均每月降价的百分率为x,则可列方程为           .

题型:单项选择题

下列不属于应收账款管理成本的有( )。

A.无法收回应收账款而发生的费用

B.对客户的资信调查费用

C.催收应收账款而发生的费用

D.因投资应收账款而丧失的利息费用

题型:单项选择题

——Look at your pale face. You ______ a sleepless night.

——You bet. The work site next to the hotel was so noisy.

A.must have had

B.might have

C.should have had

D.cannot have had

题型:单项选择题

首字母填空   (10分)

Now we live in the “computer age”. People like scientists, teachers, writers and even students use computers to do much w______. But more than 30 years ago, c________ couldn’t do much. They were very big and expensive. Quite few people were interested in them and knew how to u________ them. Today computers are smaller and cheaper. And so many people like to use them b_______ they can do a lot of work. Some even use them at home. Computers become i______ because they can work faster and make fewer mistakes. Computers can help people d______ a lot of work. Writers use them to write, students use them to s______ and children use them to play computer games. Computers can r_______ what you put into them. They are very useful and h________. They are our good f_______. We love them.

题型:单项选择题

如果某一结点要进行数据发送,在CSMA/CD控制方法中,则必须( )。

A.可立即发送

B.等到总线空闲

C.等到空令牌

D.等发送时间到

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