A.1.5~2.5 B.1.25 C.≥1.5~2.5 D.<1.25
A.20000 B.2000 C.10000 D.1000
如圖所示,R1=2W,R2=4W,R3=4W,電源電壓U=40V,則電阻R3流過(guò)的電流I3為()
A.5A B.10A C.20A D.4A