2012年高考江苏卷第13题(即计算题第1题)将交流发电机模型和辐向磁场模型糅合在一起,着重考查了学生在新情景下的建模能力和迁移能力.从阅卷反馈信息来看,学生失分情况较严重,主要原因是不能将试题与原有的发电机模型进行类比、外推,构建正确、恰当的新模型.本文从一道简单习题出发,从不同角度人手,构建两类模型,合理外推,以加深学生对这类问题的认识. 2012 college entrance examination Jiangsu volume 13 (that is, the calculation of the first question) the alternator model and the radial magnetic field model blend together, focusing on examining the students in the new situation under the modeling ability and migration ability from the feedback information The main reason is that students can not analogize and extrapolate the test questions with the original generator model to build a correct and appropriate new model.This article starts from a simple exercise and builds from different angles Two types of models, reasonable extrapolation, to enhance students’ awareness of such issues.