一个灯泡的额定电压为36V,正常发光时的电流为0.2A.求:(1)灯泡的额定功率;(2)灯泡正常发光1min消耗的电能.
问题描述:
一个灯泡的额定电压为36V,正常发光时的电流为0.2A.求:(1)灯泡的额定功率;(2)灯泡正常发光1min消耗的电能.
答
(1)U=36V,I=0.2A
据公式P=UI=36V×0.2A=7.2W;
(2)P=7.2W,t=1min=60s
据公式W=Pt=7.2W×60s=432J;
答:(1)灯泡的额定功率为7.2W,(2)灯泡正常发光1min消耗的电能为432J.