题目

I never use (wood) throwaway chopsticks. Usually l use reusable chopsticks. 答案：【1】wooden如图，R1=10Ω，R2是阻值为0～40Ω的变阻器，电源电压为12V．当P在B端时，电压表的示数多大____？当P在AB中点时，电流表___、电压表的示数各多大___？