题干

某区域的电场线分布如图所示,a、b是电场中的两点,下列说法中错误的是(   )

A:正点电荷在a、b两点受到的电场力方向必定与该点场强方向一致

B:将正点电荷由a点静止释放,仅在电场力作用下运动,该点电荷的轨迹可能与电场线一致

C:一个点电荷放在a点受到的电场力比放在b点时受到电场力大

D:a点的电场强度一定比b点的电场强度大

上一题 下一题 0.0难度 选择题 更新时间:2017-06-18 12:14:55

答案(点此获取答案解析)

B

同类题5

阅读理解

    Jeanne Calment, a French woman, became a record breaker on 17 October of 1995, when at the age of 120 years and 238 days, she became the longest-lived human being on record. A Japanese man died in 1986 at the age of 120 years and 237 days.

    Jeanne Calment lives in a small old people's home in the south of France; her husband, her only child and her grandson have all died. She is nearly blind and deaf and is always in a wheelchair, but her doctor describes her as being more like a 90-year-old in good health than someone of 120. She still has a lively sense of humor. When asked on her 120th birthday what she expected of the future, she replied: A very short one. She also remarked that she thought the good Lord had forgotten all about her.

    So what is the key to a long life? According to some doctors, diet, exercise and no smoking are the three important factors. Jeanne Calment has followed two of the tips. She has always eaten a healthy diet, and she used to do exercise every day until she broke her leg at the age of 115. However, until recently she drank two glasses of strong red wine a day, and she does smoke (now only a little). Besides, Jeanne Calment might have got very good genes from her parents. Her father lived to the age of 94 and her mother to 86.

    A local lawyer bought her house when she was 80 under an agreement that he would pay her some money every year until her death. It must have seemed a good move at the time, but so far the lawyer has paid her at least three times the value of the house. Every year on her birthday Jeanne Calment sends him a card saying: Sorry, I'm still alive!