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流過的電流I3為()
A.5A B.10A C.20A D.4A
如圖所示,若R=40W,U=100V,則電路流過的電流I為()安培
A.2.5 B.5 C.4 D.3.5