题干

如图所示,在水平向右的匀强电场中,在O点固定一电量为Q的正点电荷,a、b、c、d为以O为圆心的同一圆周上的四点,bd连线与匀强电场平行,ac连线与匀强电场垂直.则(   )

A:a、c两点的场强相同

B:b点的场强大于a点的场强

C:da间的电势差大于ab间的电势差

D:检验电荷在a点的电势能等于在c点的电势能

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答案(点此获取答案解析)

B,D

同类题3

阅读理解

    Mom was a teacher most of her life. When she wasn't in the classroom, she was educating her children or grandchildren: correcting our grammar; starting us on collections of butterflies, flowers or rocks; or inspiring a discussion on her most recent “Book of the Month Club” topic. Mom made learning fun.

    It was sad for my three brothers and me to see her illness in her later years. At eighty-five, she suffered a stroke(中风) and she went steadily(不断地) downhill after that.

    Two days before she died, my brothers and I met at her nursing home and took her for a short ride in a wheelchair. While we waited for the staff to lift her limp body back into bed, Mom fell asleep. Not wanting to wake her, we moved to the far end of the room and spoke softly. Several minutes our conversation was interrupted by a muffled sound coming from across the room. We stopped talking and looked at Mom. Her eyes were closed, but she was clearly trying to communicate with us. We went to her side.

    “Whirr,” she said weakly.

    “Where?” I asked. “Mom, is there something you want?” “Whirr,” she repeated a bit stronger. My brothers and I looked at each other and shook our heads sadly.

    Mom opened her eyes, sighed, and with all the energy she could gather said, “Not was, say were!”

    It suddenly occurred to us that Mom was correcting brother Jim's last sentence. “If it was up to me…”

    Jim leaned down and kissed her cheek. “Thanks, Mom,” he whispered. We smiled at each other and once again shook our heads…this time in awe (敬畏) of a remarkable teacher.

同类题4

请从下面的两题中任选一题作文
(1)题目:责任
提示:做一个有责任心的人,是时代的需要。有人把“天下兴亡,匹夫有责”改为“天下兴亡,我有责”。意思是说,“我”应当义不容辞地担负起对国家、对社会的责任。的确,我们每一个人都应当做一个有贵任心的人,都应当承担起自己的责任。国家遇到了困难,学校出现了问题,家庭产生了矛盾,同学违反了纪律,自己成绩不理想……都应当问一问:“我应当承担什么责任?”
要求:可以写自己的经历,也可以写别人的故事;可以从正面写,也可以从方面写;可以抒发情感,也可以发表议论。除诗歌外,文体自选。600字以上。
(2)阅读下面材料。然后按要求完成作文。
站在篮下投一次篮,难吗?当然不难。但如果长年累月每天要你练习投篮500次,你能做到吗?有一个球队做到了,这就是美国UCI_A篮球队,教练名叫约翰任顿。他要求每位球员每天站在篮下5米处练习500次基本投篮动作,他曾领导这支球队连续拿过10次全美比赛冠军。对准高尔夫球挥起一杆,难吗?当然也不难。但如果要你坚持50年,每天早上起来挥杆1000次,你能做到吗?有一个人做到了,他就是美国高尔夫球名将布雷尔,在比赛中他能准确地挥出完美无缺的一杆。
投一次篮,挥一次杆,这都是很简单的事,也都是你我能做到的事,但把这样简单的事一遍又一遍不厌其烦地做下去,坚持10年、20年、30年的又有几人呢?当然最后的成功者也就是这凤毛鳞角的凡人。
读完上述材料。结合你自身的经历、感受、认识和体验,以“坚持”为话题,写一篇作文。
要求:①除诗歌外,文体自选;题目自拟。
②600字以上。书写规范工整。
③文中不得出现真实的人名、地名、校名等透露个人身份的信息。
④作文中不可引用材料中的资料。