题目

听下面一段较长对话，回答以下小题。【1】What is the woman doing?A.She is interviewing a famous sports starB.She is having a job interview.C.She is making a self-introduction in public.【2】Why was the woman out of school for half a year during high school?A.Because she was badly ill.B.Because she had to act in a film.C.Because her father took her to America.【3】What part time job did the woman do at college?A.A designer. B.A teacher. C.A travel guide.如图所示，R1=400Ω，R3的变阻范围是0～20Ω，电源电压U保持12V不变．（1）当K断开、滑片P滑到B点时，电路消耗的总功率是1.2W，求R2的阻值；（2）当K闭合、滑片P滑到A点时，求电路中每分钟释放的总热量．