小张为了研究“当电阻R两端的电压不变时,通过R的电流与其电阻的关系”,设计了如图

题型:实验题

问题:

小张为了研究“当电阻R两端的电压不变时,通过R的电流与其电阻的关系”,设计了如图甲所示的电路,并选用了若干只不同阻值的定值电阻。

(1)请按图甲所示的电路,用笔画线代替导线,把图乙中的实物连接图补充完整;

(2)闭合开关后,发现电压表示数接近电源电压,电流表指针有明显偏转,但无论怎样移动变阻器的滑片,两表示数均不变。原因是:_________________;

(3)排除故障后,重新做实验。每次更换不同的定值电阻R后,都应移动变阻器的滑片,使________的示数不变(选填“电压表”或“电流表”)。他记下了4次实验的电阻值和对应的电流值,描绘成图丙;

(4)由图丙可知,定值电阻R两端的电压是_________V;

(5)由图丙可我们可得到结论:____________________________________。

考点:探究电流与电压、电阻的关系
题型:实验题

在报表管理系统的下列操作中,可打开“定义公式”对话框的有()。

A.单击"fx"按钮

B.双击某公式单元

C.按"="键

D.按"+"键

题型:实验题
阅读下面的短文,根据短文中的信息完成文后的表格(每空一词)
Do you know how to keep fish at home?
The fish need room(空间). They must not be crowded(拥挤). Fish need oxygen(氧气). Fish get it from water in the tank. There must be enough water for all fish in the tank. So the size of the tank is important..
In the tank many people put small plants. They give oxygen to the water. Plants help in other ways, too. Fish can nibble(轻咬)on the plants. They hide in the plants and sleep, lay eggs there.
Both the plants and fish need light. You can put it near a window. It will get light there. But remember: a window may let cold air in. The cold can kill(杀死) your fish. Too hot water can kill your fish, too.
The fish need food and you should feed them every day. Giving them too much food is bad. It will make the water dirty. However, the fish should get just enough food. They should finish the food in 10 minutes. No extra(多余) is left. When this happens, the amount(数量)of food is right.
How to keep fish at home
Advice
_______小题1:_____
1.The ___小题2:___ of the tank is important
Fish need enough room because they will be crowded in a small tank. They need __小题3:____ water because they get oxygen from it.
2.You can put small plants in the tank
Plants can give oxygen to the water, they also give a ____小题4:___ to fish to hide, sleep and lay eggs
3.You can put the tank ___小题5:___ a window, but don’t let cold air in.
Light is __小题6:____ for fish and plants. It can get in through the window. But you shouldn’t ___小题7:__ cold air can also get in and cold air will kill your fish.
4.Feed the fish every day but not too ____小题8:__
Too much food makes water ____小题9:___ easily. When fish can finish ____小题10:___ food in 10 minutes, the amount of food is right.
题型:实验题

TCP的主要功能是( )。

A.进行数据分组

B.保证可靠传输

C.确定数据传输路径

D.提高传输速度

题型:实验题

不属于招标文件内容的是( )。

A.不可预见费估算
B.拟签订的合同条款
C.委托服务范围
D.投标人须知

题型:实验题

主要用来传递和转变运动形式的是()

A.机器

B.机构

C.零件

D.构件

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