Mike works very long hours every day. He usually gets up at 17:00. He has a shower and makes his breakfast. What a funny time to make breakfast! After breakfast he practices his guitar, then he puts on his jacket and goes to work. To get to work, he takes the number17 bus to the Star Hotel. The bus usually leaves at 19:15. He works all night. People love to listen to him! He gets home at 7:00, and he watches the early morning news on TV. He goes to bed at 8:30, a tired but happy man. Can you think what his job is?

+Q和﹣Q是两个等量异种点电荷，以点电荷+Q为圆心作圆，A，B为圆上两点，MN是两电荷连线的中垂线，与两电荷连线交点为O，下列说法正确的是（  ）