极限类推法是指根据有关物理规律 ,在不超出该规律适用的条件下 ,对其所涉及的变量作合理延伸 ,通过对变量取特殊值 (一般为极限值 )进行比较 ,作出相关判断 .该方法成立的依据是极限值不超出变量的取值范围 ,其适用题型多为客观型选择题 ,以下结合近年来中考 (或竞赛 )中的试 Limit analogy means that according to the relevant laws of physics, under the condition that the law does not exceed, the variable involved in it is reasonably extended, and the relevant judgment is made by comparing the variable with a special value (usually the limit value). The basis for the establishment of the method is that the limit value does not exceed the value range of the variable. The applicable question types are mostly objective multiple-choice questions. The following combination of tests in recent years (or competitions)