[{"data":1,"prerenderedAt":72},["ShallowReactive",2],{"q-fire-109-1-fire-science-039":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-109-1-火災學概要-039","fire-109-1-fire-science-039",109,1,39,"帶電物體或其附近之接地體，有突出部分或刃狀部分時，在該等前端近旁，所出現之微弱發光放電，此現象稱為？",{"A":16,"B":17,"C":18,"D":19},"電暈放電","條狀放電","火花放電","沿面放電","A",null,[],false,"本題考點：靜電放電型態的辨識，特別是電暈放電的發生條件與外觀特徵。\n【正解理由】當帶電體或其附近的接地體具有突出部、針狀或刃狀等曲率半徑很小的部位時，該處電場特別集中，會使前端近旁的空氣局部游離而發出微弱光暈；但游離區並未貫穿到對面電極，放電通道不連通，電荷是持續而緩慢地被中和，能量很小。題幹同時給出突出部分或刃狀部分、前端近旁、微弱發光三個要件，正是電暈放電的定義。故選 A。\n【逐項排除】\n(A) 正確。電暈屬局部放電，只在尖端附近的高電場區發生游離，發光微弱且能量最低。\n(B) 條狀放電是帶電體與曲率較大的接地體接近時，由電暈進一步發展成樹枝狀、條狀延伸的放電，發光明顯、能量遠大於電暈，與題幹所述的微弱發光不符。\n(C) 火花放電是兩電極間空氣的絕緣被完全破壞、電荷在瞬間貫穿釋放，伴隨強光與爆音，能量集中，是可燃性混合氣最典型的引火源，並非局部微弱發光。\n(D) 沿面放電發生在絕緣物表面帶電密度極高時，放電沿著固體表面呈樹枝狀強烈擴展，常見於高絕緣性液體注入槽車或薄膜捲取作業，其發光強度與能量都遠大於電暈。\n【記憶點】看到尖端、刃狀加上微弱發光就是電暈；貫穿加爆音是火花；沿著絕緣物表面樹枝狀擴展則是沿面放電。","靜電放電依電極形狀、電荷密度與間距不同而呈現不同型態，能量由小到大大致依序是電暈放電、條狀（刷狀）放電、沿面放電、火花放電。電暈能量最小，是因為游離只發生在針尖或刃口附近電場特別集中的極小區域，並未貫穿到對面電極，電荷被持續而緩慢地中和掉。也正因如此，電暈常被反過來利用：除電器（離子產生器）就是刻意以針狀電極製造電暈，產生正負離子去中和帶電體上的電荷；避雷針尖端的尖端放電也是同一原理。\n火花放電則是電場強度超過空氣的絕緣破壞強度，放電通道一次貫穿兩電極，電荷在極短時間內全部釋放，伴隨強光與爆音。沿面放電發生於絕緣物表面單側帶電密度極高時，放電沿著固體表面樹枝狀擴展，常見於高絕緣性液體注入槽車、粉體投入或塑膠薄膜高速捲取作業，能量也相當可觀。\n判別時可用關鍵詞記憶：電暈看尖端加微弱發光，條狀看曲率較大的接地體接近加樹枝狀延伸，火花看貫穿加爆音，沿面看沿著絕緣物表面。\n引火風險則要對照最小著火能量來比較：一般碳氫化合物氣體約零點二至零點三毫焦耳，電暈的能量通常低於此值，因此多半不足以引燃；但氫氣、乙炔、二硫化碳的最小著火能量只有百分之幾毫焦耳，電暈就可能成為火源，粉塵的最小著火能量則多在數毫焦耳到數十毫焦耳之間。延伸考點包括各放電型態的能量排序與外觀比較、除電器的作用原理，以及靜電引起火災爆炸必須同時具備帶電、放電與可燃性混合氣三個條件。另需留意電暈雖然能量最低，卻會持續產生臭氧與氮氧化物並使絕緣材料劣化，長期而言仍是電氣設備故障與絕緣破壞的伏筆，這一點常與其引火風險低的特性一併對照命題。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-109-1-fire-science-038","在橡膠中混入碳黑所製成的產品可防止人體帶靜電，其防止靜電發生的方法為？",38,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-109-1-fire-science-040","有關預混合火焰特性，下列敘述何者錯誤？",40,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-109-1-fire-science-037","D 類火災可使用的滅火劑，何者適合？",37,{"webId":41,"stem":42,"number":12,"year":43,"session":12},"fire-110-1-fire-science-001","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？",110,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-109-1-fire-science-036","房間的體積為 V=6 m×5 m×3 m，其中 O2 占 0.21 V，請問至少要加入多少公升（L）的 CO2 讓燃燒作用無法持續？",36,{"webId":49,"stem":50,"number":51,"year":43,"session":12},"fire-110-1-fire-science-002","依據建築物火災 t2 成長理論，當釋熱率（Q）達到 4 MW 時，需要 300 秒的時間，表示火災成長之速度為下列何者？",2,[53,57,61,65,68],{"webId":54,"year":55,"stem":56,"number":13},"fire-113-1-fire-science-039",113,"有關於液化石油氣之性質與事故發生之處置原則，下列敘述何者錯誤？",{"webId":58,"year":59,"stem":60,"number":13},"fire-112-1-fire-science-039",112,"假設定量乙醇(C2H5OH)與理論空氣量混合後產生完全燃燒，其後將燃燒廢氣冷卻至常溫，則其中二氧化碳的濃度約為多少%？",{"webId":62,"year":63,"stem":64,"number":13},"fire-111-1-fire-science-039",111,"撕下新購的電視機螢幕保護封膜時遭受靜電，其原因為下列何者？",{"webId":66,"year":43,"stem":67,"number":13},"fire-110-1-fire-science-039","某建築物內部的空氣溫度為 27 ℃，發生火災的房間溫度為 627 ℃，流入該起火房間的空氣體積流量為 4 m3\u002Fs，若忽略燃燒熱分解過程而產生的質量流率，請計算流出起火房間的煙霧體積流量約為多少？",{"webId":69,"year":70,"stem":71,"number":13},"fire-108-1-fire-science-039",108,"高壓氣體的爆炸界限，通常較常壓下為廣，爆炸上限也明顯提高，但下列何種氣體之爆炸範圍及爆炸上限在高壓下卻降低？",1785129967437]