贴电阻片处的应变为l500με,电阻片的灵敏系数K=2.0,在这个电阻片上应产生的电阻变化率应是()。
A.0.2%
B.0.4%
C.0.1%
D.0.3%
参考答案:D
Mr. Black works on a big farm. His wife Mrs. Black works in a school Mr. Black is nearsighted. But he doesn’t like wearing glasses when he has meals. Mr. Black has a son. His name is Tony. He is in Class One, Grade Eight of No.2middle School. He likes talking very much. He often talks about his school and his friends at table. Mr. Black is angry, he always shouts, “Don’t talk when you have meals.” And Mrs. Black also says to him, “Be a good boy, Tony.”
One day, when they are having supper, Tony finds there is a fly in his father’s bowl. Then he wants to tell his father about it,“Dad, there is …” His father looks at him and says,“Stop talking!” After supper, his father asks him , “Well , my boy, what is it?” “There is a fly in your bowl, and it is in your stomach now.”says Tony.“Why don’t you tell me earlier?” shouts his father angrily.
小题1: Mr. Black is a .
A.farmer
B.teacher
C.driver
D.worker小题2: Mr. Li eats a .
A.bird
B.fly
C.fish
D. dog小题3: What is Tony like ? .
A.He is shy
B.He is outgoing
C.He is quiet
D.He is lazy
A.在电路中,流过两灯泡的电流相同时,发光亮度一定相同,两盏灯一定是串联的
B.在电路中,流过两灯泡的电流不相同,两盏灯一定是并联的
C.一个开关控制两盏灯泡的亮、灭,则两灯泡一定是串联
D.在电路中,两灯泡两端的电压相等时,则两灯泡一定是并联的