问题 问答题

小王家电能表上标有“220V 10A”字样,他家原有电器的总功率是1500W.最近新买了一个电热水器,铭牌上部分数据如下表所示. (计算结果保留小数点后两位数)

额定容积(L)60
额定功率(kW)1.2
额定电压(V)220
净重(Kg)25
水温调节范围(℃)10-70
(1)电热水器的额定电流是多少A?

(2)电热水器正常工作时的电阻是多少Ω?

(3)将电热水器接入家庭电路后,通过计算回答他家的用电器能否同时使用?

答案

(1)由P=UI可得:

I=

P
U
=
1.2×103W
220V
≈5.45A

(2)R=

U2
P
=
(220V)2
1200W
=40.33Ω

(3)∵电能表的额定负载功率P=UI=220V×10A=2200W

他家的用电器同时使用时,总功率为P=1500W+1200W=2700W

2700W>2200W

∴不能;

答:(1)电热水器的额定电流是5.45A;(2)电热水器正常工作时的电阻是40.33Ω;

(3)通过计算回答他家的用电器不能同时使用.

阅读理解

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