(1)∵P=
W
t ,
∴灯泡正常工作10h消耗的电能:
W=Pt=0.04kW×10h=0.4kW•h;
(2)∵P=
U 2
R ,
∴灯泡电阻R=
U 2
P =
(220V ) 2
40W =1210Ω,
电压为200V时的实际功率:
P 实际=
U ′ 2
R =
(200 V) 2
1210Ω ≈33.1W;
故答案为:0.4;33.1.
(1)∵P=
W
t ,
∴灯泡正常工作10h消耗的电能:
W=Pt=0.04kW×10h=0.4kW•h;
(2)∵P=
U 2
R ,
∴灯泡电阻R=
U 2
P =
(220V ) 2
40W =1210Ω,
电压为200V时的实际功率:
P 实际=
U ′ 2
R =
(200 V) 2
1210Ω ≈33.1W;
故答案为:0.4;33.1.