题目内容

××牌电烤箱
额定电压220V
额定
功率
高温档1100W
低温档440W
电源频率50Hz
表为一台电烤箱的铭牌,其内部简化电路如图所示,R1和R2均为电热丝,当S1、S2都闭合时,电烤箱处于    (选填“高”或“低”)温档;若当电烤箱在低温档正常工作时,电路中的电流为    A.
【答案】分析:(1)根据P=结合电路图可知,当S1、S2都闭合时,电路中的电阻最小,电热丝的电功率最大,据此确定电烤箱的温档;
(2)由表格可知,低温档位的电功率和电压,根据I=求出此时电路中的电流.
解答:解:(1)当S1、S2都闭合时,电路为R1的简单电路,电路中的电阻最小,根据P=可知此时电路中的电功率最大,即为高温档位;
(2)当电烤箱在低温档正常工作时,
电路中的电流I===2A.
故答案为:高;2.
点评:本题考查了电功率公式的灵活运用,关键是电路图的动态分析和铭牌参数含义的理解与掌握.
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