A:mustn't have drive
B:wouldn't have drive
C:can't have drive
D:shouldn't have drive
如图所示电路,电源电压为8V并保持不变。闭合开关S,当滑动变阻器的滑片P由一个位置移动到另一位置时,定值电阻R0的电功率由16W变成了4W,则电压表的示数可能( )
心 ____ ____ 亻 ____ ____ 攵 ____ ____
小 ____ ____ 广 ____ ____ 王 ____ ____