(1)两灯泡的额定电流:
I 1=
P 1
U 1 =
3W
6V =0.5A,I 2=
P 2
U 2 =
6W
6V =1A;
两灯泡的电阻:
R 1=
U 1
I 1 =
6V
0.5A =12Ω,R 2=
U 2
I 2 =
6V
1A =6Ω;
两灯泡串联时,电路中的最大电流为0.5A,即L 1正常发光、L 2不能正常发光.
(2)电源的电压U=I(R 1+R 2)=0.5A×(12Ω+6Ω)=9V;
电路的总功率P=UI=9V×0.5A=4.5W.
故选BCD.
(1)两灯泡的额定电流:
I 1=
P 1
U 1 =
3W
6V =0.5A,I 2=
P 2
U 2 =
6W
6V =1A;
两灯泡的电阻:
R 1=
U 1
I 1 =
6V
0.5A =12Ω,R 2=
U 2
I 2 =
6V
1A =6Ω;
两灯泡串联时,电路中的最大电流为0.5A,即L 1正常发光、L 2不能正常发光.
(2)电源的电压U=I(R 1+R 2)=0.5A×(12Ω+6Ω)=9V;
电路的总功率P=UI=9V×0.5A=4.5W.
故选BCD.