题干

某电阻额定电压为3V(阻值大约为10Ω).为测量其阻值,实验室提供了下列可选用的器材:

A.电流表A1(量程300mA,内阻约1Ω) 

B.电流表A2(量程0.6A,内阻约0.3Ω)

C.电压表V1(量程3.0V,内阻约3kΩ) 

D.电压表V2(量程5.0V,内阻约5kΩ)

E.滑动变阻器R1(最大阻值为10Ω) 

F.滑动变阻器R2(最大阻值为500Ω)

G.电源E(电动势4V,内阻可忽略) 

H.开关、导线若干

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    As we all know,drinking beers while running can upset the stomach.However,that's all part of the attraction of the Beer Mile,a unique race that has participants competing in running and drinking.The Beer Mile Race started off as a tradition in 1990,when a group of Canadians thought it would be fun to race each other while drinking a few beers.But it has come a long way since then.The Beer Mile Race is now a major sporting event with around 100,000 official competitors,brand name sponsors and so on.In 2015,the first Beer Mile World Classic was held in San Francisco,where all of the record holders from Canada and the United States came together for the competition.But this year,the event was organized in London,in an effort to take in more competitors about the sport outside North America.

    The rules of the race are pretty simple: runners have to consume four beers before each of the four 400-meter laps making up the famous Beer Mile.The beers can come in bottles or cans but should not be less than 355ml and must be at least 5% alcohol.The drink like apple juice will not do.Runners must drink the beers within a 10 meter zone before the start/finish line and then they are required to tip the bottle/can over their heads to confirm it is empty.

    In the case of vomiting(呕吐)during the race,and yes,there's quite a bit of that during the Beer.Mile,offenders must complete one more lap at the end of the race.Organizers mention that even in the case of vomiting several times, only one more lap must be completed.

    This year,the Elite Men's race was won by Canadian Corey Bellemore,who also set a new world record with a time of 4 minutes and 34 seconds.“I just drink the beers as quickly as I could,hold them down and get the burps(饱嗝)out,”Corey said.“If you can drink a beer in 8 seconds and also run very fast with a feeling of vomiting,then you'll be fine like me.”