我国高压直流输电起步较晚,但发展迅速,以下哪些是我国直流输电电压等级序列()。
A.±500
B.±660
C.±800
D.±1050
参考答案:A, B, C
如图所示,一个活塞将绝热容器分成A、B两部分,用控制栓K固定活塞.保持A体积不变,给电热丝通电,则此过程中气体A的内能______,温度______;拔出控制栓K,活塞将向右移动压缩气体B,则气体B的内能______.
编写如下事件过程: Option Base 1 Private Sub Form_Click( ) Dim x1( )As Integer Dim i As Integer Dim s As Integer ReDim x1(3) For i = 1 To UBound(x1) x1(i)= i + 1 Next i Call sub1(x1) For i = 1 To UBound(x1) s = s + x1(i) Next i Print s End Sub Private Sub sub1(n( )As Integer) Dim i As Integer ReDim Preserve n(5) For i = 3 To 5 n(i)= n(i - 1)* 2 Next i End Sub 程序运行后,单击窗体,则窗体上显示的内容是________。
A.6
B.12
C.24
D.47