题目一:根据W=Pt,得Q=W=450W*60s=27000焦耳
题目二:P=U^2/R=220^2/1210=40W
W=Pt=40W*600s=24000焦耳
题目三:电功率P=W/t=6.6*10^4J/60s=1100W
因为P=UI,所以U=P/I=1100W/5A=220V,所以R=U/I=220V/5A=44欧
题目一:根据W=Pt,得Q=W=450W*60s=27000焦耳
题目二:P=U^2/R=220^2/1210=40W
W=Pt=40W*600s=24000焦耳
题目三:电功率P=W/t=6.6*10^4J/60s=1100W
因为P=UI,所以U=P/I=1100W/5A=220V,所以R=U/I=220V/5A=44欧