阅读下面的材料,在空白处填入适当的词或括号内单词的适当形式。
Were you the first or the last child in your family? Or were you a middle or an only child? Some people think matters where you were born in your family. But there are different ideas about what birth order means. Some people say that the oldest children,
are smart and strong-willed, are very likely
(succeed). The reason
this is simple. Parents have a lot of time for their first child and give him or her a lot of attention. An only child will succeed for
same reason.
What happens to the children in the family? Middle children don’t get so much attention, so they don’t feel that important. If a family has many children, the middle one sometimes gets lost in the crowd. The youngest child,
, often gets special treatment. Often this child grows up to be funny. But a recent study saw things quite
(difference). The study found that first children believed in family rules. They didn’t take many chances in
lives. They usually
(follow) orders. Rules didn’t mean as much to later children in the family. They took chances and they often did better in life.
(1)读出图中游标卡尺(20等分)和螺旋测微器的读数:
图a的读数为_________cm.图b读数为___________cm.
某同学将量程为200μA、内阻为500Ω的表头μA改装成量程为1mA和10mA的双量程电流表,设计电路如图(a)所示。定值电阻R1=500Ω,R2和R3的值待定,S为单刀双掷开关,A、B为接线柱。回答下列问题:
(1)将开关S置于“1”挡时,量程为_______mA;
(2)定值电阻的阻值R2=________Ω,R3=________Ω(结果取3位有效数字)
一个匝数为100的导体线圈垂直磁场放置,在0.5s内穿过它的磁通量从1.0×10-3Wb增加到9.0×10-3Wb。则线圈中的感应电动势大小为 V
一定值电阻R=10Ω,流过它的电流I=10A。则该电阻的电功率是 W,经过2秒,电阻R生成的焦耳热为 J,经过1小时,电阻消耗电能为 度。
如图所示,劲度系数为k的轻质弹簧两端分别与质量为
的小木块A.B栓接,整个系统处于平衡状态,现竖直向上施力,将木块A缓慢上提,使木块B刚脱离接触面,在此过程中木块A产生的位移大小是_______________。