本题目来源于试卷: gc textbook chapter 18 Electric Currents，类别为 IB物理学
[问答题]
When electric lights are operated on low-frequency ac (sa+cpa54yb mqik)i0.t,.r pc8my5ifndy, 5 Hz), theyf)do exinvgjz)6 )ixvz j.5 / fxto-9f92m7vj flicker xnjj/ 5eo)izgmz d x)ivv-.69ftj 7f9x ov2)f noticeably. Why?
参考答案:
At
only 10 Hz, the metal filament in the wire will go on and off 20 times per
second. (It has a maximum magnitude of
current at the maximum current in each direction.) The metal filament has time to cool down and
get dim during the low current parts of the cycle, and your eye can detect
this. At 50 or 60 Hz, the filament never
cools enough to dim significantly.
本题详细解析:
暂无
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