⑴ 当S1闭合,单刀双掷开关K2接a时,L与R并联
∵灯泡L正常发光 ∴U=6V
⑵ 当S1断开,单刀双掷开关S2接b时,L与R串联
IL=PL/UL=3/6=0.5A
IR=IL=0.5A
R=UR/IR=(6-3)/0.5=6Ω
⑶ ∵IL=0.5A ,UL=3V,t=1min=60s
∴W=UIt=3×0.5×60=90J
⑴ 当S1闭合,单刀双掷开关K2接a时,L与R并联
∵灯泡L正常发光 ∴U=6V
⑵ 当S1断开,单刀双掷开关S2接b时,L与R串联
IL=PL/UL=3/6=0.5A
IR=IL=0.5A
R=UR/IR=(6-3)/0.5=6Ω
⑶ ∵IL=0.5A ,UL=3V,t=1min=60s
∴W=UIt=3×0.5×60=90J