(1)R2、R3串联后电阻为R串=R2+R3=4Ω+6Ω=10Ω,R串与R1并联后电阻为R分=5Ω,再与R4串联后总电阻为R总=R分+R4=5Ω+3Ω=8Ω,
此时电路电流I总=
=U R总
A=0.3A2.4 8
R4两端的电压U4=I总R4=0.3A×3Ω=0.9V,
所以R2、R3串联后两端的电压为U串=U-U4=2.4V-0.9V=1.5V,
R2、R3串联后电流I分=
=U串
R2+R3
=0.15A1.5 4+6
R3两端的电压为U3=I分R3=0.15A×6Ω=0.9V,
电阻R3、R4两端的电压之和也就是电压表的示数U分=U3+U4=0.9V+0.9V=1.8V.
故答案为:1.8V