[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-109-1-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-109-1-火災學概要-008","fire-109-1-fire-science-008",109,1,8,"1 度電為 1,000 瓦．小時（1 kWh），試問 1 度電約等同多少千卡（kcal）？",{"A":16,"B":17,"C":18,"D":19},"420","746","860","1,000","C",null,[],false,"本題考點：功與熱量的單位換算，把電能單位 1 度電(kWh)換算為熱量單位千卡(kcal)。\n【正解理由】1 度電即 1 kWh,是 1,000 瓦持續 1 小時所作的功；瓦特定義為每秒 1 焦耳，故 1 kWh＝1,000 W×3,600 s＝3.6×10⁶ J。再以熱功當量 1 cal＝4.186 J(即 1 kcal＝4,186 J)換算,3.6×10⁶ J 約等於 860 千卡，與選項數值相符，故選 C。\n【逐項排除】\n(A) 420 約為正確值的一半，常見於把熱功當量 4.186 誤當成 8.4 或多除一次 2 所致，與 3.6×10⁶ J 的實際熱量不符。\n(B) 746 是 1 馬力(HP)＝746 W 的功率換算數字，屬功率單位而非熱量單位，套用於本題屬張冠李戴。\n(C) 3.6×10⁶ J÷4,186 J\u002Fkcal≈860 kcal,數值與單位皆吻合，為應選項。\n(D) 1,000 直接取自題幹「1,000 瓦」的數字，把功率(W)當成熱量(kcal)搬用，混淆了兩種物理量。\n【演算步驟】1 kWh＝1,000 W×3,600 s＝3.6×10⁶ J;熱功當量 1 kcal＝4,186 J;3.6×10⁶ J÷4,186 J\u002Fkcal≈860.0 kcal。\n【記憶點】一度電約 860 千卡，算法就是 3.6×10⁶ 除以 4,186。","這題背後是焦耳的熱功當量實驗：焦耳以重物下落帶動槳葉攪拌水，把機械功轉成水的內能，量出「使 1 公克水升溫 1℃ 所需的熱量」與機械功的定量關係，確立熱與功是同一種量的不同形式,1 cal＝4.186 J(以 15℃ 卡為準，不同定義下 4.184～4.19 之間微幅差異，考試取 4.18 或 4.2 皆得同一選項)。\n消防考試常用的能量換算網絡值得整組記住:1 W＝1 J\u002Fs;1 kWh＝3.6 MJ＝860 kcal;1 kcal＝4.186 kJ;1 BTU≈1.055 kJ;1 kg 水升溫 1℃ 需 1 kcal;水的汽化潛熱約 539 kcal\u002Fkg(2,257 kJ\u002Fkg)。由此可推算：一度電的熱量可讓 8.6 公斤的水從 0℃ 升到 100℃,或使約 1.6 公斤的 100℃ 水完全汽化——這正是水之所以是最有效冷卻藥劑的量化理由。\n這組換算在火災學裡到處出現。熱釋放率的單位 kW 其實就是 kJ\u002Fs,所以「1 MW 火災」等於每秒釋放 1,000 kJ、約 239 kcal;火載量以 MJ\u002Fm² 表示，常需與木材等值(1 kg 木材約 18～20 MJ)互換；燃燒熱以 kJ\u002Fg 或 kcal\u002Fkg 給定，兩套單位混用時最容易出錯。\n易混淆對照則是「功率」與「能量」的分野：瓦特、馬力、熱釋放率都是功率(每單位時間);焦耳、卡、度電、BTU 都是能量。本題四個選項恰好把這兩類混在一起——746 是功率換算、1,000 是題幹的功率數字，只有先確認要換算的是「能量」,才不會被誤導。常見變化題型包括問 1 kWh 等於多少 MJ、電熱器功率乘以使用時數求耗電度數，或以熱釋放率乘燃燒時間求總釋熱量。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-109-1-fire-science-007","進入石化工廠，車輛會被要求在排氣管加裝滅焰器（flame arrester）以避免火災爆炸之發生，加裝該措施防制火災爆炸之原理為：",7,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-109-1-fire-science-010","有水之場所的插頭應加裝何種裝置以防止感電發生？",10,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-109-1-fire-science-006","某次閃電的過程中，雲的底部和地面之間，電壓高達 1 千萬伏特，並在約 0.02 秒內輸送 20 庫倫的電量至地面。下列與閃電有關的敘述何者正確？",6,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-109-1-fire-science-011","某一線徑 2.0 m\u002Fm 之電線 1 km 長之電阻值為 5.657 Ω，熱阻抗為 378。若周遭溫度為 20℃，當此 10 cm 長之電線通過 10 安培時，其芯線溫度（℃）約為多少？",11,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-109-1-fire-science-005","下列有關二氧化碳（CO2）滅火劑之敘述，何者錯誤？",5,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-109-1-fire-science-012","下列常見之乾粉滅火藥劑敘述何者正確？",12,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-114-1-fire-science-008",114,"有關災害搶救標準作業程序之敘述，何者正確？",{"webId":58,"year":59,"stem":60,"number":13},"fire-113-1-fire-science-008",113,"第五類公共危險物品自反應物質（A 型及 B 型）及有機過氧化物（A 型及 B 型），在 GHS 標示的象徵符號為何？",{"webId":62,"year":63,"stem":64,"number":13},"fire-112-1-fire-science-008",112,"赤磷和黃磷分屬我國法定公共危險物品那一類？",{"webId":66,"year":67,"stem":68,"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":70,"year":71,"stem":72,"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？",1785129967239]