不少学生在应用欧姆定律、电功、电热及其等量关系式处理具体问题时 ,不能自如运用所学知识 ,而是生搬硬套 ,因而往往出错 ,究其原因根本问题是对定律成立的条件和定律的真正含义没有全面、深刻的理解 ,因此在教学中必须对以下几个问题重点讲清 .1.欧姆定律与焦耳定律成立的条 Many students, when applying Ohm’s law, electric power, electric heat, and their equal relations to deal with specific problems, are not able to freely use what they have learned, but are immature, and thus often make mistakes. The fundamental reason for this is the conditions for the establishment of laws. The true meaning of the law does not have a comprehensive and profound understanding. Therefore, we must focus on the following issues in teaching: 1. The establishment of Ohm’s Law and Joule’s Law