题目如图所示,电源总电压为6V6V6V保持不变,R1=5ΩR _{1} =5ΩR1=5Ω,R2=10ΩR _{2} =10ΩR2=10Ω,当开关SSS由闭合到断开时,电压表VVV的示数将( )(\:\:\:\:)()A.由2V2V2V变为6V6V6VB.由4V4V4V变为6V6V6VC.由4V4V4V变为2V2V2VD.6V6V6V保持不变知识点:欧姆定律在串、并联电路中的应用章节:未标注