[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-107-1-fire-science-008":3},{"subject":4,"subjectSlug":5,"subjectKicker":6,"subjectShort":7,"question":8,"related":27,"sameNumber":52,"hasEssay":26},"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":13,"stem":14,"options":15,"answer":20,"answerNote":21,"images":22,"imagesPending":23,"lawTimestamp":11,"explanation":24,"explanationDeep":25,"freq":12,"indexable":26},"fire-107-1-火災學概要-008","fire-107-1-fire-science-008",107,1,8,"描述熱傳遞（heat transfer）之物理量為下列何者？",{"A":16,"B":17,"C":18,"D":19},"溫度","熱通量","熱釋放率","熱焓","B",null,[],false,"本題考點：熱如何被「量化描述」,考溫度、熱通量、熱釋放率、熱焓四個物理量的定義分辨。\n【正解理由】熱傳遞是熱能穿過某一界面移動的過程,要描述它必須同時講清楚「多少能量、通過多大面積、經過多久」。熱通量(heat flux)的定義正是單位時間內通過單位面積的熱能,單位為 kW\u002Fm²,能把傳導、對流、輻射三種途徑的強度用同一把尺量化;火災學判斷可燃物是否被引燃、消防人員可承受的輻射曝露上限,也都以熱通量表示,故選 B。\n【逐項排除】\n(A) 溫度是分子平均動能的指標,屬狀態量,只說明物體此刻多熱,不含面積與時間,無法表達熱移動的快慢。\n(B) 熱通量兼具方向與強度,單位 kW\u002Fm² 直接對應「每秒每平方公尺」的熱能傳遞率,是描述熱傳遞的標準物理量,為正解。\n(C) 熱釋放率描述燃燒中的可燃物每秒放出多少能量,單位為 kW,量的是火源本身的規模,屬於熱能的「產生」而非「傳遞」。\n(D) 熱焓為內能加上壓力與體積乘積的熱力學狀態函數,單位 kJ\u002Fkg,用於計算反應熱與相變熱,同樣不含傳遞面積與時間。\n【記憶點】會「傳」的看熱通量 kW\u002Fm²、會「燒」的看熱釋放率 kW,溫度與熱焓只講狀態。","熱通量之所以是火災學的核心物理量,關鍵在於三種熱傳途徑最後都能化成同一單位互相比較。傳導依傅立葉定律 q\" = k(dT\u002Fdx),k 為熱傳導係數(W\u002Fm·K),材料越導熱、溫度梯度越陡,熱通量越大;對流依牛頓冷卻定律 q\" = h(Ts − T∞),h 為對流熱傳遞係數,火場天花板噴流與煙層流動即屬此類;輻射依史蒂芬-波茲曼定律 q\" = εσT⁴,σ = 5.67×10⁻⁸ W\u002Fm²·K⁴,四次方關係使火焰溫度稍微上升,輻射熱通量便急遽放大,這正是閃燃前輻射主導的原因。三者算出來都是 kW\u002Fm²,可以直接相加比較,溫度與熱焓做不到這件事。\n數值對照可以整組記:一般可燃物長時間承受 10 kW\u002Fm² 以上即可能起火,木材引燃的臨界熱通量約 12 kW\u002Fm²,閃燃常以地板面約 20 kW\u002Fm² 為判定門檻,人體皮膚在 2.5 kW\u002Fm² 下數十秒即感疼痛。口訣是「地板 20、木材 12、皮膚 2.5」。\n易混淆對照:熱釋放率是火源尺度,以質量燃燒速率乘上燃燒熱估算;熱通量是接收端每平方公尺承受的強度。同一支火焰無論站遠站近,熱釋放率不變,接收到的熱通量卻大致隨距離平方反比衰減——這個差別是選擇題最常設計的誘答點。熱焓與比熱則用於計算把物質加熱到某溫度所需的能量,是評估冷卻滅火效果的基礎。\n延伸考點:同一組定義常改考單位對應(kW\u002Fm²、kW、kJ\u002Fkg、K 各屬哪個量),或問火場初期以何種熱傳為主(對流與傳導)、閃燃後以何者為主(輻射)。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-107-1-fire-science-007","可燃物於無明火等火源之條件下，在大氣中僅因受熱而開始自行燃燒所需之最低溫度稱為下列何者？",7,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-107-1-fire-science-009","要做好火災預防工作，從理論觀點上，可由火災預防之「3E 政策」著手，下列敘述何者不屬於「3E 政策」項目？",9,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-107-1-fire-science-006","危害物質災害現場搶救標準作業程序（H.A.Z.M.A.T.）之說明，下列何者為正確？",6,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-107-1-fire-science-010","下列有關二氧化碳滅火劑之敘述，何者錯誤？",10,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-107-1-fire-science-005","根據美國防火協會危險物品表示規定，將危險類別記載於菱形方塊上，其中黃色表示何種危害？",5,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-107-1-fire-science-011","在高科技無塵室作業中，下列敘述何者不是避免人員帶靜電產生危害之處理方式？",11,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-111-1-fire-science-008",111,"空氣氧之重量占整體之 23%，故 1 公斤碳完全燃燒需要多少空氣？",{"webId":58,"year":59,"stem":60,"number":13},"fire-110-1-fire-science-008",110,"根據美國防火協會危險物品標示規定，將危險類別記載於菱形方塊上，其中「有害健康毒性」以何種顏色表示？",{"webId":62,"year":63,"stem":64,"number":13},"fire-109-1-fire-science-008",109,"1 度電為 1,000 瓦．小時（1 kWh），試問 1 度電約等同多少千卡（kcal）？",{"webId":66,"year":67,"stem":68,"number":13},"fire-108-1-fire-science-008",108,"若乙烷的燃燒熱為 350 kcal\u002Fmole，依據 Burgess-Wheeler 法則，下列何者最為接近乙烷的燃燒下限？",{"webId":70,"year":71,"stem":72,"number":13},"fire-106-1-fire-science-008",106,"硫磺固體之燃燒屬於下列何種燃燒型態？",1785123163541]