① Q=Cm⊿t=4200J/KG*℃*100kg*(40℃-20℃)=8400000J
② E=4200000 J/h*5h=21000000J
③ η= Q/ E*100%=8400000J/21000000J*100%=40%
④ Q=m煤*q,
m煤= Q/ q=8400000J/42000000J/KG=0.2 KG
① Q=Cm⊿t=4200J/KG*℃*100kg*(40℃-20℃)=8400000J
② E=4200000 J/h*5h=21000000J
③ η= Q/ E*100%=8400000J/21000000J*100%=40%
④ Q=m煤*q,
m煤= Q/ q=8400000J/42000000J/KG=0.2 KG