有關(guān)電能表轉(zhuǎn)數(shù)問題的新解法

1、.有關(guān)電能表轉(zhuǎn)數(shù)問題的新解法DIV.MyFav_1314066389459 P.MsoNormalTEXT-JUSTIFY: inter-ideograph; FONT-SIZE: 10.5pt; FONT-FAMILY: "Times New Roman" TEXT-ALIGN: justifyDIV.MyFav_1314066389459 LI.MsoNormalTEXT-JUSTIFY: inter-ideograph; FONT-SIZE: 10.5pt; FONT-FAMILY: "Times New Roman" TEXT-ALIGN: ju

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7、-MODE: char; FONT-FAMILY: "Times New Roman"DIV.MyFav_1314066389459 P.p0TEXT-JUSTIFY: inter-ideograph; FONT-SIZE: 10.5pt; FONT-FAMILY: "Times New Roman" TEXT-ALIGN: justifyDIV.MyFav_1314066389459 LI.p0TEXT-JUSTIFY: inter-ideograph; FONT-SIZE: 10.5pt; FONT-FAMILY: "Times New R

8、oman" TEXT-ALIGN: justifyDIV.MyFav_1314066389459 DIV.p0TEXT-JUSTIFY: inter-ideograph; FONT-SIZE: 10.5pt; FONT-FAMILY: "Times New Roman" TEXT-ALIGN: justifyDIV.MyFav_1314066389459 DIV.Section1page: Section1近幾年中考題中對電能表的考察頗多，通過對電能表的觀察，理解其用處及各種技術(shù)參數(shù)的物理意義，使學(xué)生能根據(jù)電能表的示數(shù)變化計(jì)算消耗的電能。下面就2019年中考題為例

9、探究有關(guān)電能表轉(zhuǎn)數(shù)問題的新解法。例12019 年黃石市李明家中購置了一臺空調(diào)，購置時廣告宣傳牌上標(biāo)識有“1.5匹，制冷量3500W，他查資料發(fā)現(xiàn)1.5匹1100瓦。李明想測量空調(diào)在一般情況下的實(shí)際功率，他只讓空調(diào)工作，在6min內(nèi)觀察到他家的電能表的表盤轉(zhuǎn)過了60轉(zhuǎn)，電能表上標(biāo)有600r / kW·h。那么此時空調(diào)的實(shí)際功率為_W。解析：題目中給出了電能表的參數(shù)600r / kW·h，它表示的的物理意義是用電器每消耗1kW·h的電能，電能表表盤就轉(zhuǎn)動600轉(zhuǎn)。我們可以把這個參數(shù)表示為電能表的轉(zhuǎn)速符號用v表示，電能表在一定時間內(nèi)表盤轉(zhuǎn)過的轉(zhuǎn)數(shù)用符號n表示。那么用電器

10、消耗的電能可用公式計(jì)算。所以=0.1kW·h，空調(diào)的實(shí)際功率為=0.1Kw=1000w。例22019年威海電子式電能表表盤上標(biāo)有“3200imp/kw·h字樣imp表示閃爍次數(shù)。將某用電器單獨(dú)接在該電能表上正常工作30min，電能表指示燈閃爍了320次，該用電器在上述時間內(nèi)消耗的電能為kw·h，該用電器的額定功率是W。解析：電子式電能表的脈沖就是閃燈、閃一次就是表示轉(zhuǎn)一圈，閃多少次轉(zhuǎn)多少圈這個在電表上有標(biāo)注。題目中給出了電能表的參數(shù)3200imp/kw.h，它表示的的物理意義是用電器每消耗1kW·h的電能，電能表閃燈就閃動3200次。那么用電器消耗的電能：=0.1kw·h。用電器的額定功率：=0.2Kw=200w。跟蹤練習(xí)12019年湛江市小鵬同學(xué)家的電能表如圖1所示，那么小鵬家已消耗的電能為_kW?h，轉(zhuǎn)盤已轉(zhuǎn)過_轉(zhuǎn)；他發(fā)現(xiàn)家里只使用一只電水壺其它用電器都關(guān)閉時，觀察到