题干

下列说法正确的是()

A:原子核发生α衰变时,新核与α粒子的总质量等于原来的原子核的质量

B:在原子核中,比结合能越小表示原子核中的核子结合得越牢固

C:按照玻尔理论,氢原子核外电子从半径较小的轨道跃迁到半径较大的轨道时,电子的动能减小,电势能增大,原子的总能量不变

D:太阳辐射的能量主要来自太阳内部的热核反应.

上一题 下一题 0.0难度 选择题 更新时间:2018-06-21 08:37:48

答案(点此获取答案解析)

D

同类题2

【加试题】为破解看病手续烦琐问题,杭州市卫生局、杭州市医疗保险管理服务局、杭州市民卡有限公司推出了“智慧医疗结算”便民服务。持卡人只要在市民卡电子帐户内预充小额费用,就可在医生诊室直接刷卡支付需现金付费的部分。

杭州市民卡是一张集成电路卡,具有信息储存、身份识别、电子支付等功能。每位市民卡的卡号是唯一的,卡内会记录每位市民的姓名、住址、金额等信息。

假设共有100000个市民,市民的卡号、姓名和金额分别存放在数组a、b和数组c中,a(i)是存放第i个市民的卡号,则对应的第i个市民的姓名存放在b(i)中,金额存放在c(i)中。

通过卡号查询其姓名和余额的程序界面如图所示。在文本框Text1中输入卡号,单击“开始查询”按钮,如果找到,就在Label1中显示卡内市民姓名和金额;否则显示“查无此人”。已知卡号按照从小到大排序。请按要求将下列程序补充完整。

Dim a (1 To 100000) As long

Dim b (1 To 100000) As string

Dim c (1 To 100000) As long

Private Sub Command1_Click()

Dim x As Long, i As Long, j As Long, m As Long, f As Boolean

x = Val(Text1.Text)

i = 1: j = 100000: f = False           、

Do While  i<=j and f=false       

          ①        

If x= a(m) Then

        f = True

    ElseIf x< a(m) Then

        j = m - 1

    Else

             ②       

    End If

 Loop

 If f=false Then

        Label1.Caption =”查无此人”

    Else

         Label1.Caption = b(i)+ "卡内余额为"+ Str(c(i)) + "元"

    End If

 End Sub

 Private Sub Form_Load()

     ’ 此过程用于对数组a、b和c进行初始赋值,代码略

 End Sub

同类题3

   About 21,000 young people in 17 American states do not attend classes in school buildings.
   Instead, they receive their elementary and high school education by working at home on computers. The center for Education Reform says the United States has 67 public “cyberschools(网络学校)” and that is about twice as many as two years ago.
   The money for students to go to a cyberschool comes from the governments of the states where they live. Some educators say cyberschools receive money that should support traditional public schools. They also say it is difficult to know if students are learning well.
Other educators praise this new form of education for letting students work at their own speed. These people say cyberschools help students who were unhappy or unsuccessful in traditional schools. They say learning at home by computer ends long bus rides for children who live far from school.
   Whatever the judgment of cyberschools, they are getting more and more popular. For example, a new cyberschools called Commonwealth Connections Academy will take in students this fall. It will serve children in the state of Pennsylvania from ages five through thirteen.
Children get free equipment for their online education. This includes a computer, a printer, books and technical services. Parents and students talk with teachers by telephone or by sending emails through their computers when necessary.
   Students at cyberschools usually do not know one another. But 56 such students finished studies at Western Pennsylvania Cyber Charter School recently met for the first time. They were guests of honor at their graduation.