《电功率》单元测试题一（参考答案）

1、.?电功率?单元测试题一参考答案DIV.MyFav_1297928978753 P.MsoNormalTEXT-JUSTIFY: inter-ideograph; FONT-SIZE: 10.5pt; FONT-FAMILY: Times New Roman; TEXT-ALIGN: justifyDIV.MyFav_1297928978753 LI.MsoNormalTEXT-JUSTIFY: inter-ideograph; FONT-SIZE: 10.5pt; FONT-FAMILY: Times New Roman; TEXT-ALIGN: justifyDIV.MyFav_12979

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6、: Arial Unicode MSDIV.MyFav_1297928978753 DIV.Section1page: Section1DIV.MyFav_1297928978753 OLMARGIN-BOTTOM: 0cmDIV.MyFav_1297928978753 ULMARGIN-BOTTOM: 0cmA卷一、选择题1A 2D 3D 4D 5A 6A 7C二、填空题8单位 快慢 瓦 500940 251041074101011120 2120.6 0.9 1080 1.8三、综合题13解：1电阻R的功率P1=9W-4W=5W；电阻R两端的电压；灯泡正常发光时的电压也为10V2通过灯泡的

7、电流；灯泡的电阻14解：12B卷一、选择题1A 2D 3B 4A 5A 6D二、填空题78 4.884 4 2.2591000 导线的电阻比电炉小得多，一样时间内产生的热量也小得多100.04 1.2112.7812电压一定时，电阻消耗的电功率与该电阻阻值成反比三、实验与计算1310.75 灯泡越亮，小灯泡消耗的电功率越大2增大3如图14解：1由图甲知，当Ia0.2A时，Ua2.0V，所以Ra102由图甲知，当Ib0.2A时，Ub1.0V，所以Rb5PbI2Rb0.2A250.2WW总I2R串t0.2A210560s36J151S12解：；电热丝R的电功率为P=460W-20W=440W ；答：电吹风吹热风时，一分钟消耗27600J的电能。电热丝R的电功率为440W。通过电热丝R的电流为2A。16解：1电流表示数；U2=UU1=12V8V=4V ；滑动变阻器R2消耗的电功率：P=U2I=4V0.5A=2W2；I3=II1=0.75A0.25A=0.5A；根据欧姆定律，得R3的值：附加题答案：1如以下图2由图像可知：0时，热敏电阻的阻值为250，此时，电路的电流是：，所以气温表的0应与电流表刻度盘的0.