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问题 问答题

（1）有一个未知电阻R，用图1中P和Q两种电路分别对它进行测量，用P图电路测量时，两表读数分别为5.5V，0.49A，用Q图电路测量时，两表读数分别为4.4V，0.50A，则用______ 图所示电路测该电阻的阻值误差较小，测量值Rx=______，测量值比真实值偏______填“大”或“小”）．

（2）某同学通过实验研究小灯泡的电流与电压的关系．可用的器材如下：电源（电动势3V，内阻1Ω）、电键、滑动变阻器（最大阻值20Ω）、电压表、电流表、小灯泡、导线若干．

①实验中移动滑动变阻器滑片，得到了小灯泡的U-I图象如图2a所示，则可知小灯泡的电阻随电压增大而______（填“增大”、“减小”或“不变”）

②根据图2a，在图2b中把缺少的导线补全，连接成实验的电路（其中电流表和电压表分别测量小灯泡的电流和电压）

答案

（1）两种接法中，电压表示数变化大，说明电流表内阻较大，为减小实验误差，电流表应采用外接法，即采用Q所示电路图；

电阻测量值RX=

U
I
=
4.4V
0.50A
=8.8Ω；电流表采用外接法，由于电压表的分流作用，电流测量值偏大，电阻测量值比真实值小．

（2）①由灯泡的伏安特性曲线可知，随电压增大，电流增大，但△U＞△I，由R=

U
R
=
△U
△I
可知电阻阻值变大；

②由灯泡伏安特性曲线可知，灯泡最大电流为0.5A，电流表选0～0.6A，灯泡最大电压为2.2V，电压表选0～3V量程，

电流表采用外接法，滑动变阻器采用限流接法，实验电路图如图所示．

故答案为：（1）Q；8.8Ω；小；（2）①增大；②电路图如图所示．

单项选择题

某单位依据《电子信息系统机房设计规范GB 50174—2008》设计该单位的机房，在该单位采取的下述方案中，______是不符合该规范的。

A．整个机房由主机房、辅助区、支持区和行政管理区等四个功能区组成
B．主机房内计划放置15台设备，设计使用面积65平方米
C．除主机房外，还设置了辅助区，辅助区面积是主机房面积的10%
D．主机房设置了设备搬运通道、设备之间的出口通道、设备的测试和维修通道
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填空题

Bill Gates receives honorary knighthood


Britain’s Queen Elizabeth stands with Microsoft chairman and philanthropist Bill Gates after presenting him with an honorary knighthood at Buckingham Palace, London, March 2, 2005.
Sir Bill Not quite. Proclaiming himself "humbled and delighted," Microsoft founder Bill Gates received an honorary knighthood Wednesday from Queen Elizabeth Ⅱ—an accolade that allows the recipient to use "KBE" after his (1) , but not to put "Sir" in front of it.
One of the world’s richest men, Gates, 49, was (2) honored for his charitable activities around the world and his contribution (3) enterprises in Britain.
Past recipients of the honorary knighthood (4) from Irish singer Bob Geldof to former U.S. President Ronald Reagan.
"This (5) is particularly poignant given the deep connections Microsoft enjoys (6) the United Kingdom," said Gates, whose company employs about 2000 people in (7) .
Gates’ royal honor—bestowed by the queen on the advice of the (8) —was announced in January 2004, but a "mutually convenient" date to (9) it had not been available until now.
British recipients of knighthoods are entitled to be (10) with a "Sir" before their names. The honor was long the (11) of senior soldiers, judges and other servants of the state, but recent years have seen the creation of Sir Paul McCartney, (12) Mick Jagger and Sir Elton John.
As an American, Gates is not entitled to use (13) before his name, but he can put the initials KBE—Knight Commander of the (14) Empire—after his name.
Gates joins a roster of American (15) that includes former presidents Reagan and George H.W. Bush, comedian (16) Hope, retired U.S. Army Gen. Tommy Franks and former Secretary of (17) Colin Powell.
Gates said he was proud of what he called (18) "special relationship" with Britain.
"The U.K. was the first country in (19) Microsoft set up a subsidiary outside the U.S., and our experience in the (20) has been significant in shaping our international growth," he said.
Microsoft’s British facilities include Research Cambridge, a laboratory established in 1997 in the university town that employs 80 scientists. In 2000, the Bill & Melinda Gates Foundation announced a donation of $210 million to Cambridge University to create a scholarship program for graduate students from outside Britain.
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