一束激光以入射角i=30°照射液面,其反射光在固定的水平光屏上形成光斑B,如图所

题型:选择题

问题:

一束激光以入射角i=30°照射液面,其反射光在固定的水平光屏上形成光斑B,如图所示,如果反射光斑位置向右移动了2cm,说明液面(  )

A.上升了cm

B.上升了cm

C.下降了cm

D.下降了cm

考点:光的反射定律激光
题型:选择题

小题1:   People use money to buy food, furniture, books, bicycles and hundreds of other things they need or want. When they work, they usually get paid in money.

Most of the money today is made of metal or paper.   小题2: One of the first kinds of money was shells.

Shells were not the only things used as money. In China, cloth and knives were used. In the Philippine Islands, rice was used as money for a long time. Elephant tusks, monkey tails and salt were used as money in parts of Africa.

The first metal coins were made in China. They were round and had a square hole in the centre. 小题3:    Different countries have used different metals and designs for their money. 小题4:  Sweden and Russia used copper (铜) to make their money. Later some countries began to make coins of gold and silver.

But even gold and silver were inconvenient if you had to buy something expensive. Again the Chinese thought of a way to improve money. 小题5:   The first paper money looked more like a note from one person to another than the paper money used today.

Money has had an interesting history from the days of shell money until today.

A.The first coins in England were made of tin (锡).

B.But people used to use all kinds of things as money.

C.No one knows for certain when people began to use money.

D.People strung (串连) them together and carried them from place to place.E. Money, as we know, is all made of paper.

F. They began to use paper money.

G. Today anyone will accept money in exchange for goods and services.

题型:选择题

工业污水监测项目中对电子、仪器、仪表的监测项目正确的是( )。

A.悬浮物

B.表面活性剂

C.氰化物

D.氯化物

题型:选择题

关于心脏标志物应用原则,下列哪项说法不正确()

A.心脏肌钙蛋白(cTnT或cTn取代CK-MB成为检出心肌损伤的苜选标准

B.临床检验中应同时检测cTnT和CM-MB质量,确保诊断无误

C.如果患者已有典型的可确诊急性心肌梗死的ECG变化,应立即进行治疗

D.对发病6小时后的就诊患者,不必测Mb,只需测定cTn

E.肌钙蛋白比CK-MB出现更早

题型:选择题

电焊是利用()作为加热源进行焊接的一种工艺方法。

A、热能

B、电能

C、光能

D、机械

题型:选择题

在一定条件下,进行熔指分析时,样品的重量由()决定.

A.指数大小

B.温度高低.

C.强度

D.电性能

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