题干

关于电源电动势概念的认识中,正确的是:(    )

A:电源电动势等于电源两极间的电压

B:在闭合电路中,电动势等于路端电压与电源内部电势降落之和

C:电动势与电压单位相同,所以物理意义也相同

D:电源把其他形式的能转化为电能越多,电动势就越大

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答案(点此获取答案解析)

B

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    Time is very important in our life. However, I had never realized it until I received a beautiful gold watch from my father one day when I was 19 years old. This watch always 1 me the importance of time in my life.
   It was a cold rainy day. My father asked me to go to the 2to pick up my uncle and take him home. I should have arrived there before 4:30p.m. We had a basketball match at school that afternoon and the match was so 3that I forgot the time. When the match was nearly over, I suddenly remembered my uncle and hurried to the airport .It was too late. He had left the airport and take a taxi to our house.
   I was very worried that my father would complain 4the thing. As soon as I entered the living room, I saw my uncle in the sofa looking very tired. I do not 5uncle and my father .I said hello to them in a very low voice .My father didn’t say 6.Instead, he asked me to sit7 him. “Peter, did you have a good time today?” I felt so sorry and answered in a 8 voice. “Yes, Dad, but I ’m really sorry .This will9happen again. I promise.”My father handed me a box with a beautiful gold watch inside .It was a gift my uncle bought for him. He gave it to me and said, “I hope you have learned something important today, and this watch will help you remember the importance of time.”
   The watch has been with me for twelve years .I wear it not because of its price, but because of 10I learned. It tells me to respect(重视)and never be late to do what I have promised to .