解答:已知:UL=6V,PL=3W,I=1.5A,t=1min=60s
求:RL,R0,W
解:(1)灯泡正常发光时灯丝的电阻为 RL=
=
U
PL
=12Ω;6V×6V 3W
(2)U=U0=UL,
IL=
=PL UL
=0.5A,3W 6V
I0=I-IL=1.5A-0.5A=1A,
故定值电阻R0的阻值为 R0=
=U0 I0
=6Ω;6V 1A
(3)W=UIt=6V×1.5A×60s=540J.
答:(1)小灯泡L正常发光时灯丝的电阻为12Ω;
(2)定值电阻R0的阻值为6Ω;
(3)通电1min电路消耗的总电能为540J.