题干

如图所示的电路中,电压U保持不变,电阻R1=R2,开关s断开时,电流表的示数为I1;开关S闭合时,电流表的示数为I2,则I1:I2=____ 。

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答案(点此获取答案解析)

1:2

同类题3

阅读下面的文言文,完成下列小题。

    既至秦,持千金之资物,厚秦王宠臣中庶子蒙嘉。

    嘉为先言于秦王曰:“燕王诚振怖大王之威,不敢兴兵拒大王,愿举国为内臣,比诸侯之列,给贡职如郡县,而得奉守先王之宗庙。恐惧不敢自陈,谨斩樊於期头,及献燕之督亢之地图,函封,燕王拜送于庭,使使以闻大王。唯大王命之。”

    秦王闻之,大喜。乃朝服,设九宾,见燕使者咸阳宫。

    荆轲奉樊於期头函,而秦武阳奉地图匣,以次进。至陛下,秦武阳色变振恐,群臣怪之,荆轲顾笑武阳,前为曰:“北蛮夷之鄙人,未尝见天子,故振慑,愿大王少假借之,使毕使于前。”秦王谓轲曰:“起,取武阳所持图!”

    轲既取图奉之,发图,图穷而匕首见。因左手把秦王之袖,而右手持匕首揕之。未至身,秦王惊,自引而起,绝袖。拔剑,剑长,操其室。时恐急,剑坚,故不可立拔。

    荆轲逐秦王,秦王还柱而走。群臣惊愕,卒起不意,尽失其度。而秦法,群臣侍殿上者,不得持尺兵;诸郎中执兵,皆陈殿下,非有诏不得上。方急时,不及召下兵,以故荆轲逐秦王,而卒惶急无以击轲,而乃手共搏之。

    是时,侍医夏无且以其所奉药囊提轲。秦王方还柱走,卒惶急不知所为。左右乃曰:“王负剑!王负剑!”遂拔以击荆轲,断其左股。荆轲废,乃引其匕首提秦王,不中,中柱。秦王复击轲,被八创。

    轲自知事不就,倚柱而笑,箕踞骂曰:“事所以不成者,乃欲以生劫之,必得约契报太子也。”(选自《荆轲刺秦王》)

同类题4

根据短文理解,回答下列问题。

    The Internet is becoming more and more important in our life. How much do you know about it? What is the Internet? The Internet is a large, worldwide collection of computer networks. A network is a small group of computers put together. The Internet is many different networks from (A)                 the world. These networks are called the Internet. Once you have learned to use the Internet, you can have a lot of interest in the World Wide Web.

    What is the World Wide Web?

    The World Wide Web has been the most popular development of the Internet. The Web is like a big electronic book with millions of pages. These pages are called homepages. You can find information about almost anything in the world on these pages. For example, (B) you can use the Internet instead of a library to find information for your homework. You can also find information about your favourite sports or film stars, talk to your friends or even do some shopping on the Internet. Most pages have words, pictures and even sound or music.

    What is e-mail? (C)电子邮件是给别人发送信息的一种方法。 It's much quicker and cheaper than sending a letter. If you want to send e-mails, you must have an e-mail address. This address must have letters and dots(点 ) and an ‘@’( meaning ‘at'). This is what an address looks like: Emily @ star. net. Write a message, type in the person's e-mail address, and then send the message on the Internet. People don't need to use stamps, envelopes or go to the post office since the invention of the Internet. Quick. easy and interesting--that's the Internet!