题目

已知中子的质量为mn=1.6749×10－27kg，质子的质量为mp=1.6726×10－27kg，氚核的质量为mT=5.0076×10－27kg，1eV=1.60×10－19J，则氚核的比结合能为（ ）A.1.10MeV B.2.19MeVC.2.78MeV D.8.33Mev 答案：【答案】C【解析】核反应方程为该反应的过程中，质量的减小为该反应释放的核能氚核的比结合能为故选C。Ten-year-old Obama was one of the only three black students at his school in Honolulu, Hawaii. The young boy didn't look the same as most other students. White girls wanted to touch his hair. A white boy asked him whether his father ate people. "I lied to them that my father was a Kenyan prince, but I kept asking myself who I was," said Obama.However, 37 years later, the boy made history. Barack Obama became the first black president in U.S. history.Obama was born on August 4, 1961. His father is a black African and his mother is a white American. This unusual background made him want to know who he was. With the help of his friends, Obama finally went to college. His hard work made him a star at Harvard University, a famous university in Massachusetts. Later, he became the third black senator(议员 ) in U. S. history.While he was competing for U.S.president, Obama talked about his background. He called for a United States of America, but not a white America or a black America. Obama's success is a historic victory. It made Martin Luther King's dream come true. That is: A man should not be judged（判断） by the color of his skin, but by the content of his character.Title: The life story of Barack Obama______1.______ On August 4, 1961Parents His father is a black from ____2._____ while his mother is a white from America.At the age of 10 The number of black students at his school is just _____3.___He looked ____4.______ most other students.In college He got lots of ______5.______ from his friends.He grew popular among the students because of _____6.____Later He became _____7._____ in the U.S. history._____8.____ He called for a United States of America.He won the ____9.___ for the U.S. president.He _____10.___ Martin Luther King's dream.