题目

小军利用如图所示装置探究电阻产生的热量与电流大小的关系，当电路正常工作且通电时间一定时，电阻    产生的热量多；若通过R1的电流为1A，通电时间为10s时，阻值为10Ω的电阻R2产生的热量为    J。 答案：R1；25。 【分析】（1）由图知，R2与R3并联后与R1串联，由并联电路的电流特点和Q＝I2Rt判断R1与R2产生热量的多少； （2）先由并联电路特点计算R2的电流大小，再根据Q＝I2Rt求通电10s时R2产生的热量。 【解答】解： （1）由图可知，R2与R3并联后与R1串联， 由并联电路的电流特点可知，I1＝I2+I3，所以I1＞I2单词拼写根据题意及所给单词的首字母或汉语提示，写出单词的正确形式，将单词完整地写在答题卡上，每空一词。（共10小题，每小题1分，满分10分）【1】The guide told me to take care of my ________(护照) during traveling abroad.【2】It is very hot and dry, don’t forget to ________(浇水) the flowers.【3】We haven’t done sports ________(自从) we began to prepare for the graduation exam.【4】On Children’s Day, primary school students always go to the ________(公园) and spend their holiday in it.【5】The ship “The East Star(东方之星)” turned over and sank on ________(六月) 1st, with more than 400 people killed.【6】The head teacher should stay in t______ with parents more often.【7】It is Tuesday today and it will be W______ tomorrow.【8】As we all know, the Y_______ River is the second longest river in our country.【9】The little bird is lovely, but it is too young to eat by i______.【10】There are usually t______ days in February in a year.