1、填空题  对于升压变压器，原线圈的匝数?（“多于”或“少于”）副线圈匝数。

2、简答题  一小型水电站，其交流发电机的输出功率为1000kW，输出电压为1000V，在输电过程中，要求能量损耗为总功率的4%，已知输电线电阻为16Ω，用户降压变压器的输出电压为240V，求送电线路中，升压变压器与降压变压器的匝数比各为多大？

3、选择题  如图所示，理想变压器的原线圈a、b两端接正弦交流电压，副线圈c、d两端通过输电线接两只相同的灯泡L1、L2，输电线的等效电阻为R，当开关由原来的闭合状态变为断开时，下列各量中减小的是（　　）
A．副线圈c、d两端的输出电压
B．副线圈输电线等效电阻R上的电压
C．通过灯泡L1上的电流强度
D．原线圈上的电流强度
600)makesmallpic(this,600,1800);\' alt=\"91考试网\" src=\"http://www_php168_com/91files/2016060407/01ide2uabcn.png\">

4、选择题  通过一理想变压器，经同一线路输送相同的电功率P，原线圈的电压U保持不变，输电线路的总电阻为R．当副线圈与原线圈的匝数比为k时，线路损耗的电功率为P1，若将副线圈与原线圈的匝数比提高到nk，线路损耗的电功率为P2，则P1和style=\"shiti/data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABIAAAAtCAIAAAAsgKx4AAAAdklEQVRIieWUwQ7AIAhD+f+fdpcdDEUoZmLIeiQ+qQjI2JL8AhMQm00ddciTGNpeYjNjBFXIr8cS8/URlmJejPpfVeQwybCqSnnDjms2OFUYDmiscpM3sO6bK4H5V1Cby4gwluJsOSxsTgM7tblqMXxFs3mrwB7Ww1wVAKrGFAAAAABJRU5ErkJggg==\" alt=\"\">分别为（　　）

A.style=\"shiti/data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABgAAAAvCAIAAAB2ap26AAAAlklEQVRIie2U0RIAIQRF/f9P21d2L5LMNG2eSs1xE4gXGV3QBf0FRNoGT7EidQOxvmusaGJbAsnXBSA/R8oPKU6mzQCOnJTYHtA4BXClF+bFOQ1+bc7OB1HNGhTtCnIKMgdiu0vM6WF5g7DoAvi1bNNKJwCFUy0BKimqUN4gfx4lQAsUKRcihrWCQVZ8qyyZd2/aC+oFPY5PsujZ+RJ3AAAAAElFTkSuQmCC\" alt=\"\">? ，? style=\"shiti/data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA8AAAArCAIAAAAoiUU9AAAAV0lEQVQ4je3TywoAIAhE0fv/P12rgh5juYmw3HYaRJTkKeJokBH9A+DQvuyv1bzVh6u3aq3RdbiTZ3SdrrFY7fCLTmJvmdItbdNJ9pYeqdVJp4NeWnCdAWEcBF+bitm5AAAAAElFTkSuQmCC\" alt=\"\">
B.style=\"shiti/data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACsAAAAuCAIAAAA+8nckAAAA40lEQVRYhe2VwRLEIAhD/f+f3j109lANMVjE7Qyc2oLkVQHb57S10wBFUARvImh3c3ljCC4Z+Kx4Awi6pK7XbALlILrzchPwOlhIpa4hZWiRqZnFOMXrrgCLwFVZhEApCECwLO9djitxXE/qC3rhl3WCEIM5b2e3VR5m7tonm2C8RA7sQe+14tozCyAItPcQbIKYT0YeTSbSFgILwkpNxmL73ahzRJh6Ks8DdHlMMBVQ5HXTLlC029kExLuRIEF+TkC6MYmAJN1OMPYk7PuH8g4C64+tuRRAkGZFUARFUAT/Q/AFJDYWEsSlMicAAAAASUVORK5CYII=\" alt=\"\">R，? style=\"shiti/data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA8AAAArCAIAAAAoiUU9AAAAV0lEQVQ4je3TywoAIAhE0fv/P12rgh5juYmw3HYaRJTkKeJokBH9A+DQvuyv1bzVh6u3aq3RdbiTZ3SdrrFY7fCLTmJvmdItbdNJ9pYeqdVJp4NeWnCdAWEcBF+bitm5AAAAAElFTkSuQmCC\" alt=\"\">
C.style=\"shiti/data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABgAAAAvCAIAAAB2ap26AAAAlklEQVRIie2U0RIAIQRF/f9P21d2L5LMNG2eSs1xE4gXGV3QBf0FRNoGT7EidQOxvmusaGJbAsnXBSA/R8oPKU6mzQCOnJTYHtA4BXClF+bFOQ1+bc7OB1HNGhTtCnIKMgdiu0vM6WF5g7DoAvi1bNNKJwCFUy0BKimqUN4gfx4lQAsUKRcihrWCQVZ8qyyZd2/aC+oFPY5PsujZ+RJ3AAAAAElFTkSuQmCC\" alt=\"\">? ，? style=\"shiti/data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABYAAAAxCAIAAABRf87iAAAAc0lEQVRIie3T0Q6AIAgF0Pv/P00PrY2F7iLYMuM+uB7kBE4h6aCIrxCAV2/vA5AlJnRRxGoErqS68KcIQ2Akj3XxB4JedkLoyp4yMMgeRPw4ab3c3oj91vV8kHOHXsU8P07QH7q6eJUI13eJ4CDhFLEhcQDoZdbEd+f0bgAAAABJRU5ErkJggg==\" alt=\"\">
D.style=\"shiti/data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAADYAAAAmCAIAAAAA8f8RAAAA0klEQVRYhe3WPQ6AIAwGUO5/RW/hbuLAYkupLVD4ohAGfyB9QgHTeR3gNS0XbOIm/oCYaEEkZqV4jUJkpk3sJiLmYjZNWCu9xCgT/XI4Ypk/PJIldrPP21EgGn09+efqyInRWe8NJOQiFJFkJCCRHwpoxPLv5IWYRpSGiYYeRY04R9kQoncWon0CEbBaifxor9zy/aKyYqJGkWynleVvfBg1is+BmeZzE5WQEEQ93mLiQp+DqIdEISpRFxPLrU5sY2kWQjRu0ezV2FP0QwfgJmr1Bo251d1OxoOdAAAAAElFTkSuQmCC\" alt=\"\">R，style=\"shiti/data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABYAAAAxCAIAAABRf87iAAAAc0lEQVRIie3T0Q6AIAgF0Pv/P00PrY2F7iLYMuM+uB7kBE4h6aCIrxCAV2/vA5AlJnRRxGoErqS68KcIQ2Akj3XxB4JedkLoyp4yMMgeRPw4ab3c3oj91vV8kHOHXsU8P07QH7q6eJUI13eJ4CDhFLEhcQDoZdbEd+f0bgAAAABJRU5ErkJggg==\" alt=\"\">

5、计算题  某发电机输出功率是100kw，输出电压的瞬时值表达式为600)makesmallpic(this,600,1800);\' src=\"http://www_php168_com/91files/2016060407/onghe1dicha.gif\" style=\"vertical-align:middle;\">，从发电机到用户间的输电线总电阻为8Ω，要使输电线上的功率损失为5%，需用变压器进行升压。求：
（1）发电机输出电压U1
（2）远距离的输电线路上的电流强度I线
（3）升压变压器原、副线圈匝数比n1:n2

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