[{"data":1,"prerenderedAt":72},["ShallowReactive",2],{"q-fire-106-1-fire-science-001":3},{"subject":4,"subjectSlug":5,"subjectKicker":6,"subjectShort":7,"question":8,"related":26,"sameNumber":52,"hasEssay":25},"火災學概要","fire-science","火災學 · Fire Science","火災學",{"id":9,"webId":10,"year":11,"session":12,"subject":4,"number":12,"stem":13,"options":14,"answer":19,"answerNote":20,"images":21,"imagesPending":22,"lawTimestamp":11,"explanation":23,"explanationDeep":24,"freq":12,"indexable":25},"fire-106-1-火災學概要-001","fire-106-1-fire-science-001",106,1,"某物質每克的燃燒熱為 1 仟焦耳，若 100 克該物質於 10 秒內平均燃燒完，則該物質之熱釋放率為：",{"A":15,"B":16,"C":17,"D":18},"1 MW","1 kW","10 MW","10 kW","D",null,[],false,"本題考點：熱釋放率的定義與單位換算,亦即單位時間內因燃燒而釋放之熱能。\n【正解理由】依熱釋放率之定義,熱釋放率等於燃燒速率乘以燃燒熱,亦可直接以總釋放熱量除以燃燒所歷經之時間求得。本題每克燃燒熱為 1 仟焦耳,一百克完全燃燒共釋放 100 克 × 1 kJ\u002Fg = 100 kJ 之熱量;此熱量於 10 秒內平均釋放,故熱釋放率為 100 kJ ÷ 10 s = 10 kJ\u002Fs。依功率定義 1 J\u002Fs 等於 1 W,10 kJ\u002Fs 即為 10 kW,與選項數值及單位完全相符,故選 D。\n【逐項排除】\n(A) 1 MW 錯誤。1 MW 等於 1,000 kJ\u002Fs,較正確值大一千倍,係誤把 kJ 當成 MJ 換算所致。\n(B) 1 kW 錯誤。1 kW 對應每秒釋放 1 kJ,等於把總熱量 100 kJ 錯除以 100 秒,或漏乘一百公克的質量。\n(C) 10 MW 錯誤。數量級較正確值大一千倍,係在正確的數字 10 之後誤用百萬瓦單位。\n(D) 10 kW 正確,為應選項。100 kJ 除以 10 秒得 10 kJ\u002Fs,即 10 kW,數值與單位皆與計算結果一致。\n【記憶點】熱釋放率是「功率」不是「熱量」——先算總熱量再除以秒數,單位落在瓦而非焦耳。","熱釋放率是火災學中最核心的量化指標,常以符號 Q 表示,基本式為 Q = ṁ × ΔHc,其中 ṁ 為單位時間的質量燃燒速率(kg\u002Fs 或 g\u002Fs),ΔHc 為燃燒熱(kJ\u002Fkg 或 kJ\u002Fg)。本題把質量燃燒速率拆成「總質量除以總時間」呈現,實質上是同一條式子:100 g ÷ 10 s = 10 g\u002Fs,再乘以 1 kJ\u002Fg,同樣得到 10 kJ\u002Fs。兩種算法互為驗證,考場上可擇一使用。\n\n單位換算是本類題目的主要失分點。1 W = 1 J\u002Fs;1 kW = 1,000 W = 1 kJ\u002Fs;1 MW = 1,000 kW = 1,000 kJ\u002Fs。焦耳是能量、瓦是功率,兩者差一個時間維度,選項若給出「10 kJ」而非「10 kW」,即屬單位陷阱。另可記住幾個實務量級作為合理性檢核:一支蠟燭約 0.08 kW,一個廢紙簍火約 20 kW,一張單人沙發全面燃燒可達 1 至 2 MW,一間起居室閃燃後可達數 MW。本題結果 10 kW 大致相當於小型垃圾桶火,量級合理;若算成 10 MW,等同一間大空間全面燃燒,與一百公克物質的規模明顯不符,可立即察覺算錯。\n\n熱釋放率之所以重要,在於它同時決定火羽流溫度、頂棚噴流速度、煙層下降速率與探測器動作時間。常見延伸公式包括:火羽流中心線溫度隨高度衰減的關係、頂棚噴流估算式,以及以熱釋放率推估閃燃發生所需能量的經驗式(與開口面積及開口高度平方根乘積成正比)。這些式子都以 Q 為輸入,故熱釋放率算錯,後續全錯。\n\n易混淆概念對照:燃燒熱(單位質量放出的能量,kJ\u002Fg)與熱釋放率(單位時間放出的能量,kW)不同;熱釋放速率與火載量密度亦不同,後者是單位樓地板面積的等價可燃物量,反映的是「總量」而非「速率」。相關考點延伸:歷年常以不同單位組合出題,例如給定 kg 與分鐘,要求答 MW,此時須先把分鐘化為秒、公斤化為公克或改用 kJ\u002Fkg,再逐步代入,養成每一步都寫上單位的習慣,是避免數量級錯誤最有效的方法。",true,[27,32,36,40,44,49],{"webId":28,"stem":29,"number":30,"year":31,"session":12},"fire-114-1-fire-science-004","下列有關隧道火災之敘述何者錯誤？",4,114,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-106-1-fire-science-002","造成工業火災的最高比率因素為何？",2,{"webId":37,"stem":38,"number":30,"year":39,"session":12},"fire-112-1-fire-science-004","若空氣中的氧氣體積百分比為 21%，則甲烷完全燃燒的化學理論濃度為多少%？",112,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-106-1-fire-science-003","紅外線顯像儀器可量測下列何種量值？",3,{"webId":45,"stem":46,"number":47,"year":48,"session":12},"fire-111-1-fire-science-040","沾有油類之毛巾，集中堆置於塑膠籃而產生自然發火，其原因為下列何者？",40,111,{"webId":50,"stem":51,"number":30,"year":11,"session":12},"fire-106-1-fire-science-004","關於火災紀錄的敘述，下列何者錯誤？",[53,56,60,64,68],{"webId":54,"year":48,"stem":55,"number":12},"fire-111-1-fire-science-001","近年來已有水滅火器經型式認可，下列敘述何者正確？",{"webId":57,"year":58,"stem":59,"number":12},"fire-110-1-fire-science-001",110,"下列物質各取 1 莫耳進行完全燃燒，何者所需的理論空氣量（kg）最少？",{"webId":61,"year":62,"stem":63,"number":12},"fire-109-1-fire-science-001",109,"已知辛烷的燃燒下限為 0.92（vol%），根據 Burgess-Wheeler 定理其燃燒熱約為多少？",{"webId":65,"year":66,"stem":67,"number":12},"fire-108-1-fire-science-001",108,"假設火場中只含一種燃料且均勻分布，起火後火勢循 t2 成長理論持續成長，且火災成長常數呈定值。已知起火後第 1 分鐘燒耗燃料 1 公斤，則再經 2 分鐘後，從起火開始起算總共燒耗若干公斤之燃料？",{"webId":69,"year":70,"stem":71,"number":12},"fire-107-1-fire-science-001",107,"在火場中會因吸入下列何種氣體，導致阻礙紅血球輸氧功能而造成窒息死亡？",1785123163894]