（2013?房山区二模）如图所示，电源电压保持不变，滑动变阻器的最大阻值为20Ω，R0为防止电源短路的定值 （2012?丰台区二模）如图所示，电源电压保持不变，滑动变阻...

\uff082013?\u8499\u5c71\u53bf\u4e8c\u6a21\uff09\u5982\u56fe\u6240\u793a\uff0c\u7535\u6e90\u7535\u538bU\u4fdd\u6301\u4e0d\u53d8\uff0c\u6ed1\u52a8\u53d8\u963b\u5668R2\u7684\u6700\u5927\u963b\u503c\u4e3a20\u03a9\uff0c\u706f\u6ce1L\u7684\u7535\u963b\u4e3a10\u03a9\uff0e

\uff081\uff09\u5f53S\u95ed\u5408\uff0cS1\u65ad\u5f00\uff0c\u4e14\u6ed1\u7247P\u5728b\u7aef\u65f6\uff0c\u706f\u6ce1\u4e0e\u6ed1\u52a8\u53d8\u963b\u5668\u7684\u6700\u5927\u963b\u503c\u4e32\u8054\uff0c\u7535\u6d41\u8868\u6d4b\u7535\u8def\u4e2d\u7684\u7535\u6d41\uff0c\u2235\u4e32\u8054\u7535\u8def\u4e2d\u7684\u603b\u7535\u963b\u7b49\u4e8e\u5404\u5206\u7535\u963b\u4e4b\u548c\uff0c\u2234\u6839\u636e\u6b27\u59c6\u5b9a\u5f8b\u53ef\u5f97\uff0c\u7535\u6e90\u7684\u7535\u538b\uff1aU=I\uff08RL+R2\uff09=0.2A\u00d7\uff0810\u03a9+20\u03a9\uff09=6V\uff1b\uff082\uff09\u5f53S\u3001S1\u90fd\u95ed\u5408\uff0c\u4e14\u6ed1\u7247P\u5728a\u7aef\u65f6\uff0c\u706f\u6ce1\u4e0eR1\u5e76\u8054\uff0c\u7535\u6d41\u8868\u6d4b\u5e72\u8def\u7535\u6d41\uff0c\u2235\u5e76\u8054\u7535\u8def\u4e2d\u5404\u652f\u8def\u4e24\u7aef\u7684\u7535\u538b\u76f8\u7b49\uff0c\u2234\u901a\u8fc7\u706f\u6ce1\u7684\u7535\u6d41\uff1aIL=URL=6V10\u03a9=0.6A\uff0c\u2235\u5e76\u8054\u7535\u8def\u4e2d\u5e72\u8def\u7535\u6d41\u7b49\u4e8e\u5404\u652f\u8def\u7535\u6d41\u4e4b\u548c\uff0c\u2234\u901a\u8fc7R1\u7684\u7535\u6d41\uff1aI1=I\u2032-IL=0.8A-0.6A=0.2A\uff0c\u5219R1=UI1=6V0.2A=30\u03a9\uff1b\uff083\uff09\u6839\u636eP=U2R\u53ef\u77e5\uff0c\u706f\u6ce1\u4e0e\u6ed1\u52a8\u53d8\u963b\u5668\u7684\u6700\u5927\u963b\u503c\u4e32\u8054\u65f6\u7535\u8def\u4e2d\u7684\u7535\u963b\u6700\u5927\uff0c\u7535\u8def\u6d88\u8017\u7684\u603b\u529f\u7387\u6700\u5c0f\uff1b\u706f\u6ce1\u4e0eR1\u5e76\u8054\u65f6\u7535\u8def\u4e2d\u7684\u603b\u7535\u963b\u6700\u5c0f\uff0c\u7535\u8def\u6d88\u8017\u7684\u603b\u529f\u7387\u6700\u5927\uff0cPmax\uff1aPmin=UI\u2032\uff1aUI=I\u2032\uff1aI=0.8A\uff1a0.2A=4\uff1a1\uff0e\u7b54\uff1a\uff081\uff09\u7535\u6e90\u7535\u538b\u4e3a6V\uff1b \uff082\uff09\u7535\u963bR1\u7684\u963b\u503c\u4e3a30\u03a9\uff1b\uff083\uff09\u7535\u8def\u4e2d\u6d88\u8017\u7684\u6700\u5927\u603b\u529f\u7387\u4e0e\u6700\u5c0f\u603b\u529f\u7387\u4e4b\u6bd4\u4e3a4\uff1a1\uff0e

\uff081\uff09\u5f00\u5173S1\u3001S2\u5747\u95ed\u5408\u4e14\u6ed1\u7247P\u6ed1\u5230b\u7aef\uff0c\u7b49\u6548\u7535\u8def\u56fe\u7532\u6240\u793a\uff0cI1\u2032\u2032=I1-I2\uff0c\u2235I1\uff1aI2=7\uff1a4\uff0c\u2234I1\u2032\u2032\uff1aI2=3\uff1a4\uff0c\u5219R1RL=UI1\u2032\u2032UI2=I2I1\u2032\u2032=43\uff0cRL=34R1=34\u00d740\u03a9=30\u03a9\uff0c\u706f\u6ce1\u529f\u7387PL=U2VRL\uff0c\u7535\u538b\u8868\u793a\u6570UV=PLRL=4.8W\u00d730\u03a9=12V\uff0c\u7535\u6e90\u7535\u538bU=UV=12V\uff0c\u7b54\uff1a\u7535\u538b\u8868V\u7684\u793a\u6570\u662f12V\uff0e\uff082\uff09\u5982\u56fe\u7532\u6240\u793a\uff0cI2=URL=12V30\u03a9=0.4A\uff0c\u2235I1\uff1aI2=7\uff1a4\uff0c\u2234I1=74I2=74\u00d70.4A=0.7A\uff0c\u5f00\u5173S1\u3001S2\u5747\u65ad\u5f00\u4e14\u6ed1\u7247P\u7f6e\u4e8e\u6ed1\u52a8\u53d8\u963b\u5668\u4e2d\u70b9\uff0c\u7b49\u6548\u7535\u8def\u56fe\u5982\u56fe\u4e59\u6240\u793a\uff0c\u2235I1\u2032\u662fI1\u768437\u500d\uff0c\u2234\u7535\u8def\u7535\u6d41I1\u2032=37\u00d70.7A=0.3A\uff0c\u7535\u8def\u603b\u7535\u963bR=<table cellpadding="-1" cellspacin

由图可知：滑动变阻器R与定值电阻R₀串联．当变阻器R=10Ω时，电流表的示数为0.4A，当变阻器R′=8Ω时，电路中的总阻值减小，根据I=

U

R总

可知：电流大于0.4A；
再根据串联电路起分压作用，且变阻器两端的电压应减小，
即：应小于当变阻器R=10Ω时两端的电压U=I₁R=0.4A×10Ω=4V；
而若电路中电流为0.5A时，则变阻器两端的电压为4V，故电路中电流不可能等于或大于0.5A；
所以电路中电流为0.48A，即电流表的示数为0.48A．
故选B．

(2013?鎴垮北鍖轰簩妯)鍥剧敳涓轰竴鍒楃畝璋愭í娉㈠湪t=0.10s鏃跺埢鐨勬尝褰㈠浘,P鏄钩琛...
绛旓細A銆佺敱璐ㄧ偣Q鐨勬尟鍔ㄥ浘璞★紝璇诲嚭t=0.15s鏃讹紝璐ㄧ偣Q鐨勪綅绉讳负璐熷悜鏈澶у硷紝鍒欏姞閫熷害杈惧埌姝ｅ悜鏈澶у硷紟鏁匒姝ｇ‘锛 B銆佺敱鎸姩鍥捐薄璇诲嚭鍛ㄦ湡T=0.20s锛庣敱鎸姩璇诲嚭t=0.15s鏃讹紝Q鐐瑰浜庢尝璋凤紝鍦ㄦ尝鍔ㄥ浘璞＄湅鍑簒=2m澶勮川鐐规鏃堕氳繃骞宠　浣嶇疆鍚戜笅锛屽垯璐ㄧ偣P姝ｆ部y杞磋礋鏂瑰悜杩愬姩锛庢晠B閿欒锛 C銆佺敱鎸姩鍥捐薄鍙煡锛宼=...

(2013?鎴垮北鍖轰簩妯)鍥句负鏌愬悓瀛︽牴鎹疄楠屾暟鎹,鎻忕粯鐨勬煇绉嶇墿璐ㄥ潎鍖鏀剧儹鍙 ...
绛旓細鐢卞浘璞＄煡锛屾櫠浣撳湪鍑濆浐杩囩▼涓俯搴︿繚鎸80鈩冧笉鍙橈紝鎵浠ュ嚌鍥虹偣涓80鈩冿紝鐔旂偣涓庡嚌鍥虹偣鐩哥瓑涔熶负80鈩冿紱浠庣8min寮濮嬪嚌鍥猴紝鍒扮18min瀹屽叏鍑濆浐瀹岋紝鎵浠ュ嚌鍥鸿繃绋嬬敤浜10min锛庢晠绛旀涓猴細80锛10锛

(2013?鎴垮北鍖轰簩妯)鏌愮鐢电娉电殑缁撴瀯濡傚浘鎵绀,鎶婅鏈夋恫鎬侀挔鐨勭煩褰㈡埅闈㈠...
绛旓細锛1锛夋牴鎹乏鎵嬪畾鍒欑煡锛屾柟鍚戝瀭鐩碆I骞抽潰鍚戦噷锛庯紙2锛夋恫鎬侀挔鍦ㄥ湪纾佸満涓彈鍒板畨鍩瑰姏F=BIa瀹夊煿鍔涗綔鐢ㄧ殑闈㈢Н涓篠=ab P锛滷S锛滲Ib锛3锛夌敱I=QtQ=nqbLa鍥犱负a=v0t锛庝唬鍏ヨВ寰桰=nqbLv0 v0锛滻nqbL锛庣瓟锛氾紙1锛夋恫鎬侀挔鍙楃鍦洪┍鍔ㄥ姏鐨勬柟鍚戝瀭鐩碆I骞抽潰鍚戦噷锛庯紙2锛夊绠℃í鎴潰涓婄敱纾佸満椹卞姩鍔涙墍褰㈡垚鐨勯檮鍔犲帇寮...

(2013?鎴垮北鍖轰簩妯)___.鍏朵腑娌℃湁娑夊強鐨勮惀鍏荤礌鏄痏__.鈶＄洓鏀剧背楗殑濉戞枡椁愮洅...
绛旓細鎵ц姹借溅灏炬皵鎺掓斁鏍囧噯锛屾湁鍒╀簬鍑忓皯鎴栨帶鍒舵湁瀹崇墿璐ㄧ殑鎺掓斁锛 缁胯壊鍑鸿鏄寚浠ユ琛屾垨楠戣嚜琛岃溅鎴栧叾瀹冨舰寮忔潵浠ｆ浛姹借溅绛変氦閫氬伐鍏凤紝鏈夊埄浜庡噺灏戞薄鏌擄紱澶栧嚭鎴撮槻鎶ら潰鍏峰彧鑳戒繚鎶ゆ埓闃叉姢闈㈠叿鐨勪汉锛岃屼笌鎺у埗鎴栧噺灏戞薄鏌撴棤鍏筹紟缁间笂鎵杩帮紝寮鍙戞竻娲佽兘婧愩佹墽琛屾苯杞﹀熬姘旀帓鏀炬爣鍑嗐佺豢鑹插嚭琛岀瓑鎺柦锛屾湁鍒╀簬鍑忓皯姹℃煋锛庢晠濉細ACD锛

(2013?鎴垮北鍖轰簩妯)閽犲厓绱犲浜虹被鐢熶骇鍜岀敓娲诲叿鏈夐噸瑕佹剰涔.(1)鍦ㄥ厓绱犲懆...
绛旓細锛1锛夌敱閽犲厓绱犵殑淇℃伅锛岄挔鍏冪礌鐨勭浉瀵瑰師瀛愯川閲忎负22.99锛庯紙2锛夋阿姘у寲閽犲浐浣撴毚闇插湪绌烘皵涓槗鍚告敹姘村垎鑰屾疆瑙ｏ紝甯哥敤浣滄煇浜涙皵浣撶殑骞茬嚗鍓傦紟锛3锛夊皬鑻忔墦锛圢aHCO3锛夎兘涓庤儍閰镐腑鐨勭洂閰稿弽搴旂敓鎴愭隘鍖栭挔銆佹按鍜屼簩姘у寲纰筹紝鍙嶅簲鐨勫寲瀛︽柟绋嬪紡涓猴細NaHCO 3+HCl鈺怤aCl+H2O+CO2鈫戯紟锛4锛夊伐涓氫笂锛岄氳繃鐢佃В姘寲閽犳憾娑插埗鍙栫儳纰憋紝...

(2011?鎴垮北鍖轰簩妯)濡傚浘鎵绀 鍋氣滄祴瀹氬皬鐏场鍔熺巼鈥濈殑瀹為獙鏃,鎵鐢ㄥ皬鐏场...
绛旓細瑙ｏ紱锛1锛夌敤绾挎妸鐢垫祦琛ㄨ礋鏋佹帴绾挎煴涓庢粦鍔ㄥ彉闃诲櫒鐨凜鎺ョ嚎鏌辫繛璧锋潵锛屾妸鐢靛帇琛ㄧ殑璐熸帴绾挎煴涓庡皬鐏场宸︾鎺ョ嚎鏌辩浉杩烇紝鐢靛帇琛15V鎺ョ嚎鏌变笌灏忕伅娉″彸绔帴绾挎煴鐩歌繛锛岀數璺浘濡傚浘鎵绀猴紱鏍规嵁瀹炵墿鍥句綔鍘熺悊鍥撅紝濡傚浘鎵绀猴紟锛2锛夎绠楀姛鐜囩敤鍏紡P=UI锛屽皬鐏场鐨勯瀹氱數鍘婾=3.8V锛涚敱鍥惧彲鐭ョ數娴佽〃绀烘暟I=0.24A锛屽垯鐏场鍔熺巼P...

(2012?鎴垮北鍖轰簩妯)濡傚浘鎵绀虹數璺腑,鐢垫簮鐢靛帇U淇濇寔涓嶅彉.寮鍏砈1闂悎銆丼2鏂...
绛旓細寮鍏砈1闂悎銆丼2鏂紑锛屾粦鍔ㄥ彉闃诲櫒鐨勬粦鐗嘝璺濆乏绔45澶勬椂锛岀瓑鏁堢數璺浘濡傚浘1鎵绀猴紱寮鍏砈1銆丼2闂悎锛屼繚鎸佹粦鍔ㄥ彉闃诲櫒鐨勬粦鐗囦笉鍔紝绛夋晥鐢佃矾鍥惧鍥2鎵绀猴紟锛1锛夊浘1涓紝鐢辨濮嗗畾寰嬪彲寰楋細R2=U2I1=6.5V0.5A=13惟锛屽浘1鍜屽浘2涓紝鈭典覆鑱旂數璺腑鍚勫鐨勭數娴佺浉绛夛紝涓擯=I2R锛屸埓P1P2=I21(R2+R3)I21(R1+R2)=...

(2011?鎴垮北鍖轰簩妯)濡傚浘鐢叉墍绀,鏄祴鍔ㄦ粦杞満姊版晥鐜囩殑绀烘剰鍥.瀹冪敤寮圭哀娴...
绛旓細锛1锛夊脊绨ф祴鍔涜鐨勭ず鏁颁负1N+0.2N脳3=1.6N锛涳紙2锛夐挬鐮佷笂鍗囩殑璺濈涓哄浘涓瑼鍒癇鐨勮窛绂伙紝涓10cm锛涳紙3锛夋媺鍔汧鍋氱殑鍔焀鎬=Fs=1.6N脳0.2m=0.32J锛涳紙4锛夋粦杞粍鐨勬満姊版晥鐜囄=W鏈塛鎬=GhFs=0.2kg脳10N/kg脳0.1m0.32J=62.5%锛庢晠绛旀涓猴細锛1锛1.6锛涳紙2锛10锛 锛3锛0.32锛涳紙4锛62.5%...

(2012?鎴垮北鍖轰簩妯)鍦濡傚浘鎵绀虹殑閫氱數铻虹嚎绠′腑鏍囧嚭N銆丼鏋
绛旓細鍙虫墜鎻′綇铻虹嚎绠★紝鍥涙寚鎸囧悜鐢垫祦鏂瑰悜锛屽垯澶ф媷鎸囨墍鎸囩殑鏂瑰悜鍗抽氱數铻虹嚎绠＄殑鍙崇涓篘鏋侊紝鍙︿竴绔负S鏋侊紟濡備笅鍥鎵绀猴細

(2011?鎴垮北鍖轰簩妯)濡傚浘鎵绀,鐢ㄥぉ骞冲拰閲忕瓛娴嬮噾灞炲潡鐨勫瘑搴.灏嗘墭鐩樺ぉ骞虫斁 ...
绛旓細璋冭妭澶╁钩鏃讹紝搴斿皢娓哥爜鏀惧湪鏍囧昂鐨勯浂鍒诲害绾垮锛庡綋鎸囬拡鍋忓彸鏃讹紝璇存槑鍙充晶璐ㄩ噺澶э紝搴斿皢骞宠　铻烘瘝鍚戝乏绉诲姩锛涘浘涓ぉ骞崇殑绀烘暟涓100g+50g+4.4g=154.4g锛涢噾灞炲潡鐨勪綋绉负70cm3-50cm3=20cm3锛涢噾灞炲潡鐨勫瘑搴ο=mV=154.4g20cm3=7.72脳103kg/m3锛庢晠绛旀涓猴細闆跺埢搴︾嚎锛屽乏锛154.4锛7.72脳103kg/m3锛