22题,

来源:学生作业帮助网 编辑:作业帮 时间:2024/07/20 08:16:54
22题,
xn@_eu"a=oPE)BtLlD4Q !Q"tH\ȝ 273I]|w+IOrk6N_&eP7G}|HsbԨh6_u1o獟>ͼO9}Rŝ`&). K-3 egA.H6:Z-  "Ad1wPcw,AeeHgC !6 (ẐnY7SY"6 AUiHvůduMj9Rbfs=O2}\ۻCW_^ itŢW~v{Ta?/{~wnI-n~<9`cS/_,TgE (x/r C'?>

22题,
22题,
 

22题,
(2) 已知:P=1200W t=10min=600s t1=20° t2=100° ρ 水=1g/cm³ V=2L=2000mL c水=4.2*10^3J/(kg.° C)
求:效率η
W总=Pt=1200W*600s=7.2*10^5J
m水= ρ 水2*V=2kg
Q吸=c水*m水(t2-t1)
=4200*2*(100-20)J
=6.72*10^5J
η=Q吸/W总*100%
=93.3%
答: