1》小灯的电流为0.36安,则小灯的实际功率:
P=UI=3×0.36=1.08(W)
2》小灯的电阻:
R=U/I=3/0.36≈8.33(Ω)
3》小灯泡的额定功率:
P=U×U/R=3.8×3.8/8.33≈1.733(W)