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          1???????????????????\???Q??????????0???????L???i>R串??????????Q???i>R10U???|????36??????Q??????????  3.6   ???Q?i>RLQ?i>RQ?

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          3?????????正?Q????????????????????~?????g????????????????????????????????g????|???????????????    Q?/p>

          A. ????带??          B.????带正?

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          4?????泡?????????PZ220???100??/st1:chmetcnv>Q??室温??????????????Mؓ(f)R1Q????常工?????????????????Mؓ(f)R2=48.4Ƨ????R2?i>R1大0????q???׃?Q?nbsp;   Q?/p>

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          6?????i>L????为i>U??????Ӟ????????ؓ(f)25???????i>L?????i>R串????????????Ӟ???i>L????????为6???讄????M????????????????????    Q?/p>

              A. 2?nbsp;   B. 4?nbsp;   C. 8?nbsp;   D. 9??

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          7???????\Q????????????????R1=20Ƨ????????????表nbsp;  ??nbsp;  ???C???1Q?Q?nbsp;  ??nbsp;  ???C???5Q?Q??????正确???Q?nbsp;   Q?/p>

          A.  R2=20Ƨnbsp;   B. R3=30Ƨnbsp;   C.?|?表nbsp;  ???Cؓ(f)0.1?D.?\??????d???ؓ(f)0.8??/p>


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          8??????????20V?????使??Ӟ????为00WQ?????q??|?q????U????q????????????为1WQ??导线??????????

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          1????????|???????Q????S????Ӟ??|?表?C???.5????????????表?C???????R2??????0.2??????????C??????

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          4.8????泡?????Rq??????Q??泡?常????q\???|???.2?????串??????Q????????????????????1Q?Q???????i>R??????????.24?????????????????????

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          3??Q?i>R1=10Ƨ?R2???大??d?为0Ƨ??|????gؓ(f)8?????d?R2q???\????Mؓ(f)??Ӟ?R2??????????大???为???

           

           

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          1??nbsp;[解?]

              此?????\??Z???????L?????|?两?Q????????为0W???此?????????PL=U 2Q?i>RL=40W???????i>L??i>R串?????????????R?????ؓ(f)PR=WRQ?i>t=36JQ?0S=3.6WQ??PR=I2R=(UQ?RQ?i>RL))2?i>R=3.6WQ??两??????????PLQ?i>PR=(RQ?i>RL)2Q?i>R?i>RL=40WQ?.6WQ????RLQ?i>R=9Q???i>RLQ?i>R=1Q?Q??????????串??\?i>PL?Ԍ?PR=RLQ?i>R=9Q?Q??PL?9PR=9?3.6W=32.4W??????ؓ(f)??st1:chmetcnv TCSC="0" NumberType="1" Negative="False" HasSpace="False" SourceValue="32.4" UnitName="?? w:st="on">32.4??/st1:chmetcnv>??

          2??nbsp;[解?]

          ??????????????\??????????????为i>P?/sub>??i>P?/sub>Q?i>P?/sub>=U2/R?/sub>Q?sub>Q?????两?q????Q?i>P?/sub>?U2Q?i>R?/sub>???以/p>

          P?/sub>?Ԍ?P?/sub>=U2Q?i>R?/sub>÷U?/sub>2Q?i>R?/sub>=(UQ?i>U?/sub>)2=Q?/p>

          ?sub>??/p>

          ??????/p>

          3??nbsp;[解?]

          ???????????????????正????????????正????????q??g????U??????l?????说?g???????????Q???????????????g?????????????????Q?????|???g??????????????????P?q??????U?????????Q??U??????????????正??h?????Q?ɽ????正??????????????Q????????????正确{??为??

          4??nbsp;[解?]此???????????????正?Q???让????q??解??????gQ????????g????????对媄??????d????????????ȝ?大??????度????积??????????I?大??????????温度??????Q?????????泡?常???????????sub>Ƨ???????????????Q??以???说?????

          5??nbsp;[解?]

          ????????????P???为??????????i>U???q???i>I???w???i>R??????????.5Ƨ???串?????????????????|???????????????I1=I2Q??Q?????????d???ؓ(f)R=2Ƨ?R=1.125Ƨ?代?????|?强度?????为i>I=2??I=2.67??正确??为????

          6??nbsp;[解?]

          此???ؓ(f)两??\??Q????i>L?????|?两?Q?i>PL=25WQ?????????E?i>PL=U 2Q?i>RL=25WQ????i>L???i>R串???????\????i>L两???为i>U2Q?????????E?sub>Q??此?????Q?/p>

          Q??UQ?i>UL=5Q?,ULQ?i>UR=4Q?Q??????????ULQ?i>UR=RLQ?i>R=4Q?Q??串??\??PLQ?i>PR=RLQ?i>R=4Q?Q??PR=4W??????ؓ(f)B??

          ??????

           

          7??CD

          ???计??/p>

           

          8??nbsp;[解?]

          ?????U=220V?????P=100WQ????ؓ(f)????为i>U?Ԍ???泡??M?????Ҏ(gu)?P=U2Q?i>RQ??Q?i>PQ?i>P?U2Q?i>U1Q??以/p>

          ????Ӟ???两??????i>U??/sub>=I??/sub>R??/sub>=484Ω?9/22=198V????Ӟ????导线????为?U导/sub>=UQ?i>U??/sub>=220VQ?98V=22V???导线??????????P导/sub>Q?i>P?IU导/sub>Q?i>IU?Ԍ??????Ui>I??Q??P导/sub>=22V?81WQ?98V=9W???导线????????为???

          9??nbsp;[解?]

          此???ؓ(f)两??\??Q???????????Ӟ?R2??????R1?????|?两?Q???????ؓ(f)0.5???????????I1=UQ?i>R1=0.5A?????S??????R1??i>R2串?为????\??Q?????表??R1两???U1=4V????i>R2?????i>P2为.2????q?????????{???????E??I2=U1Q?i>R1??i>I2=P2Q?UQ?i>U1)Q??4VQ?i>R1=1.2WQ?UQ?V)???W?????????????E????解?R1=20Ω???i>I2=U1Q?i>R1=4VQ?0Ω=0.2A??????ؓ(f)??.2???

          10??nbsp;[解?]

          ?Ҏ(gu)?P=I2R

          Q??

          ?ƈ????sub>??/p>

          ?׃???????{?sub>?/p>

          ??????????I=0.4AQ?i>PL=U?i>I1=1.92W.

          11??nbsp;[解?]

          设i>R2q???\????为i>Rx?Ӟ???????????大ؓ(f)PQ????i>P=I2R???

          P=I2Rx=(UQ?RxQ?i>R1))2?i>RxQ?sub>Q?????????Q?????Ҏ(gu)?Q??=b2Q?st1:chmetcnv TCSC="0" NumberType="1" Negative="False" HasSpace="False" SourceValue="4" UnitName="ac" w:st="on">4ac?????????为??i>Rx??????ơ?E?sub>Q??为i>Rx????正?Q??以?=(20PQ?4)2Q??P?100P?Q?????P?.6?????R2?????大????为.6????i>P=1.6??????????Rx=10Ω??/p>


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