物理中很多物理现象可能涉及若干个临界状态,中学物理中把涉及两个临界状态的现象叫做双临界现象,把涉及两个双临界状态的问题叫做双临界问题。双临界问题对培养学生的分析能力和创新能力,提高学生思维的严密性、批判性和灵活性有重大意义。双临界问题又是高考的热点问题,尤其是两个临界条件是并列关系的双临界问题更是大型考 Many physical phenomena in physics may involve a number of critical states. In secondary school physics, the phenomenon involving two critical states is called the double critical phenomenon, and the problem involving two dual critical states is called the double critical problem. The double-critical problem is of great significance to cultivate students ’analytical ability and innovative ability, and to improve the rigor, criticism and flexibility of students’ thinking. Two-critical problem is the hot issue of college entrance examination, in particular, the two critical conditions are juxtaposed two-critical problem is a large test