题目

如图所示,同学们在进行“什么情况下磁可以生电”的探究.实验中尝试采用①增强磁场②增大导体切割磁感线的速度③用多匝线圈的一边代替导体ab④让导线倾斜切割磁感线⑤导体ab换成粗导体的方法来增大感应电流.能明显增大感应电流的方法是A. ①② B. ①②③ C. ①②③④ D. ①②③⑤ 答案：【答案】B【解析】感应电流的大小主要与磁场的强弱、导体切割磁感线运动的速度有关；用多匝线圈的一边代替导体ab做切割磁感线也可以增大感应电流，导线垂直切割磁感线效果最好，导体ab换成粗导体，效果不太明显；因此明显增大感应电流的方法是①②③。故答案选B根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有两项多余选项。It’s not news that we spend more time than ever texting and online.1 Yes, that’s right: a 2010 study shows that more teens are reading good old-fashioned, ink-on-paper books.Reading is a good way to discover the next big thing and to learn a little more about yourself while you’re at it.2 Here are some tips.Start with your interestsReading on your own isn’t like reading for school. You can pick something that’s all about your interests, whether it’s ancient martial arts, computers, or fashion design.Reading the blurbs(简介)The reviews and quotes on the back and inside covers of many books are called “blurbs”. 3if you find a book you really like, take a minute to read the quotes(if there are any) and see which authors praised the book. Often, they’ll have similar styles and you might find you like books by those authors too.Ask an expert4 Explain your interests--- rock stars, sports teams, historical events, humors, whatever you’re into—and any writers you like, and your librarian can point you toward books that you’ll love.Finally, you’ll probably enjoy what you’re reading a lot more if you find a quiet place and make time for the book.5 You can put on some good music(ideally without lyrics), get yourself some tea and a comfy spot, and let yourself be carried away by the book.You’ll see that time does fly when you are reading something you love!A．Join a group with your friends and people you trust.B．But do you know how to pick a book you’ll really like?C．But did you know that we also spend more time reading?D．Your local library can hook you up with a whole lot of great book ideas.E. What was your mother’s favorite book when she was your age or your dad’s?F. We all multitask, but most reading is best enjoyed when you can concentrate and focus on it.G. They give you an idea of what the book is about, and can also help you pick future books too.