人民教育出版社出版的新课标教材《物理》选修3-1第57页有如下这样一道练习题:图1电饭锅工作时有两种状态:一是锅内水烧干前的加热状态,一是水烧干后的保温状态.图1是电饭锅的电路图,R_1是一电阻,R_2是加热用的电阻丝.(1)自动开关S接通和断开时,电饭锅分别处于哪种状态说明理由 The new course textbook published by the People’s Education Publishing House “Physics” elective 3-1 page 57 has the following exercises: Figure 1 The rice cooker has two working states: First, the heating state before the water in the pot is dried. First, the insulation state after the water is dried. Figure 1 is the circuit diagram of the rice cooker, R_1 is a resistor, and R_2 is a resistance wire for heating. (1) When the automatic switch S is turned on and off, the rice cooker is separately In what kind of state explain the reason