[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-108-1-fire-science-022":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-108-1-火災學概要-022","fire-108-1-fire-science-022",108,1,22,"物體在 327℃時的輻射強度為 E，則當溫度升高到 927℃時的輻射強度為何？",{"A":16,"B":17,"C":18,"D":19},"16 E","8 E","4 E","64 E","A",null,[],false,"本題考點：史蒂芬－波茲曼定律中「輻射強度與絕對溫度四次方成正比」的關係，以及攝氏轉絕對溫度的換算。\n【正解理由】依史蒂芬－波茲曼定律，物體單位面積的輻射能 E＝εσT⁴，式中 T 必須是絕對溫度（K＝℃＋273）。327℃ 換算為 600 K，927℃ 換算為 1200 K，兩者絕對溫度比為 1200÷600＝2 倍；輻射強度比即為 2 的四次方，等於 16 倍，故選 A。\n【逐項排除】\n(A) 16 E：絕對溫度由 600 K 升至 1200 K 恰為 2 倍，四次方後得 2⁴＝16 倍，完全符合 E∝T⁴，為正解。\n(B) 8 E：係把指數誤記為三次方（2³＝8）所得；史蒂芬－波茲曼定律的指數是 4，不是 3。\n(C) 4 E：把輻射誤當成與絕對溫度平方成正比（2²＝4），多為與對流、動壓等平方關係的公式混淆所致。\n(D) 64 E：把 2 倍溫度比錯用成六次方（2⁶＝64），或誤以為攝氏數值也要另乘倍率，與四次方定律不合。\n【記憶點】輻射看的是「絕對溫度的四次方」，溫度加倍，輻射就是十六倍。","史蒂芬－波茲曼定律 E＝εσT⁴ 是火災學輻射熱傳的骨幹：σ 為史蒂芬－波茲曼常數 5.67×10⁻⁸ W\u002Fm²·K⁴，ε 為放射率（黑體為 1，火焰與一般建材約 0.7～0.95），T 必須是絕對溫度。指數 4 的物理意義在於，溫度只要小幅上升，輻射熱通量就以四次方倍率成長，這正是火場閃燃前後輻射熱急遽攀升、隔著相當距離仍能引燃可燃物的原因。\n常用門檻可一併記住：人體皮膚短時間可耐約 2.5 kW\u002Fm²，木材等一般可燃物在約 10～12.5 kW\u002Fm² 的持續輻射下會被引燃，閃燃階段地板面的輻射熱通常已超過 20 kW\u002Fm²。反推之，1000℃（1273 K）的黑體輻射強度約 149 kW\u002Fm²，可見火場輻射的量級之大。\n三個易混淆處：其一，攝氏未換算為絕對溫度是本題型最大失分點，直接以 927÷327 相除必錯；其二，輻射熱通量隨距離依平方反比衰減（點源近似），與 T⁴ 分屬兩個層次，題目問哪一個要看清；其三，維恩位移定律 λmax·T≈2898 μm·K 描述的是輻射波長分布（火焰由暗紅轉為黃白即溫度上升的表徵），與總能量的四次方定律不同。\n延伸考點：本定律用於推算防火間隔與延燒範圍、判斷輻射熱是否足以引燃鄰棟外牆開口；也常與對流熱傳（牛頓冷卻定律 q＝h·ΔT，與溫差一次方成正比）、傳導熱傳（傅立葉定律 q＝−k·dT\u002Fdx）在同一題組對照命題。常見變化題是改問「輻射強度變為 81 倍時絕對溫度為幾倍」，解法同樣是先換算 K 再開四次方，得 3 倍。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-108-1-fire-science-021","依據建築物火災 t2 成長理論，在一定義為快速成長的火災中，釋熱率達到 1MW 的時間應為多少秒？",21,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-108-1-fire-science-023","乙醇在閃火點時的飽和蒸汽壓為 25 mmHg，則乙醇在常壓下的燃燒下限約為何？",23,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-108-1-fire-science-020","下列何種滅火劑所含成分之一，於放射後有刺激呼吸之作用，可有效降低場內人員的窒息危害？",20,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-108-1-fire-science-024","下列有關燃燒上下限之敘述，何者錯誤？",24,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-108-1-fire-science-019","下列何種滅火劑使用於金屬火災時，沒有「與金屬產生化學反應而衍生危害物質」的可能？",19,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-108-1-fire-science-025","木材受熱分解進而燃燒的過程中，當加熱到引火溫度時，可燃性氣體釋出量迅速增加，試問木材的引火溫度約為多少℃？",25,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-111-1-fire-science-022",111,"連棟式木造建築物引發火災，消防隊射水同時拆除未受火勢波及的房屋，請問其採取的滅火方法係下列何者？",{"webId":58,"year":59,"stem":60,"number":13},"fire-110-1-fire-science-022",110,"火災中所產生的輻射熱量與下列何者成正比？",{"webId":62,"year":63,"stem":64,"number":13},"fire-109-1-fire-science-022",109,"預防過氧化丁酮之火災爆炸時，下列何種原則正確？",{"webId":66,"year":67,"stem":68,"number":13},"fire-107-1-fire-science-022",107,"燃燒塔每分鐘需消耗 5.8 kg 之丁烷（C4H10），請估算在 NTP（25℃，1 大氣壓）之條件下，此燃燒塔每小時所需之燃燒理論空氣體積（LV）約為下列何者？",{"webId":70,"year":71,"stem":72,"number":13},"fire-106-1-fire-science-022",106,"水的滅火效果，下列何者正確？",1785123163253]