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> 王梅发现她家新买的白炽灯用过一段时间后,在相同电压下发光时要暗一些,从物理学的角度看是因为灯发光时,温度升高,灯丝发生了现象(填物态变化的名称),使灯丝变细,导致灯-八年级物理
王梅发现她家新买的白炽灯用过一段时间后,在相同电压下发光时要暗一些,从物理学的角度看是因为灯发光时,温度升高,灯丝发生了现象(填物态变化的名称),使灯丝变细,导致灯-八年级物理
题目简介
王梅发现她家新买的白炽灯用过一段时间后,在相同电压下发光时要暗一些,从物理学的角度看是因为灯发光时,温度升高,灯丝发生了现象(填物态变化的名称),使灯丝变细,导致灯-八年级物理
题目详情
王梅发现她家新买的白炽灯用过一段时间后,在相同电压下发光时要暗一些,从物理学的角度看是因为灯发光时,温度升高,灯丝发生了
现象(填物态变化的名称),使灯丝变细,导致灯丝电阻变
,消耗的实际功率变
的缘故.
题型:填空题
难度:中档
来源:不详
答案
升华;大;小
试题分析:白炽灯的灯丝用钨制成,钨的熔点为3000多摄氏度,而灯泡发光时的温度低于钨的熔点,所以钨不会熔化,而是直接变为气态,发生了升华现象导致灯丝变细,电阻变大,根据公式
可知,实际功率变小。
上一篇 :
阅读理解。 In the past, Amer
下一篇 :
下列物态变化中属于升华现象的
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题目简介
王梅发现她家新买的白炽灯用过一段时间后,在相同电压下发光时要暗一些,从物理学的角度看是因为灯发光时,温度升高,灯丝发生了现象(填物态变化的名称),使灯丝变细,导致灯-八年级物理
题目详情
答案
试题分析:白炽灯的灯丝用钨制成,钨的熔点为3000多摄氏度,而灯泡发光时的温度低于钨的熔点,所以钨不会熔化,而是直接变为气态,发生了升华现象导致灯丝变细,电阻变大,根据公式