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月考复习八上物理|超声波与次声波考点

  • 2026-09-29 00:44:30
月考复习八上物理|超声波与次声波考点

月考复习八上物理｜超声波与次声波考点

八上物理2.3重点：超声波、次声波，选择题高频！
✅超声波：频率＞20000Hz，人耳听不到
应用：B超、倒车雷达、超声波清洗、超声波碎石
✅次声波：频率＜20Hz，人耳听不到
应用：监测地震、火山、台风；次声波会伤害人体

⚠️易错点：人耳听不到超声、次声，不是没有声音。
整理实例速记，预习复习直接用，搞定选择填空✨

#标签
#八年级物理 #超声波次声波 #初中物理 #声现象

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小学五年级语文苏教版第一二单元试卷及答案

基本 文件 流程 错误 SQL 调试
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  10. SELECT * FROM `fenlei` WHERE `id` = 65 LIMIT 1 [ RunTime:0.000329s ]
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  15. SELECT * FROM `article` WHERE `id` < 517445 ORDER BY `id` DESC LIMIT 20,10 [ RunTime:0.000636s ]
0.079036s