PHY. 問題~

早前出左條數學題，大家都解答左，多謝晒大家~
呢條PHY 題目係我唔太了解GE，請大家解答一下~
(一張係問題，一張係圖)   (字體問題請見諒= =  )  

If the water level is higher, the laser beam hits the liquid earlier,
if the water level is lower, the laser beam hits the liquid later,
the reflect beam will hit the sensor at different locations.
By measuring how far will the laser hit the sensor, it is able to calculate the level of the liquid.

孖吉 發表於 2012-10-28 23:57
If the water level is higher, the laser beam hits the liquid earlier,
if the water level is lower,  ...

................

孖吉 發表於 2012-10-28 23:57
If the water level is higher, the laser beam hits the liquid earlier,
if the water level is lower,  ...

嗯嗯，明白~   咁
When laser beam reach water surface, will it cause diffuse reflection?

技術之達人 發表於 2012-10-29 21:59
嗯嗯，明白~   咁
When laser beam reach water surface, will it cause diffuse reflection?

Not on smooth surfaces like water.

Actually, a laser beam is so strong that it can survive several reflections, below is a green laser bouncing several times inside a thick piece of glass. You can see that not much diffuse reflection is observed (remember, glass is a frozen liquid).

laser beam bouncing

講到physics我可以摺埋lu~

問題係通5到呢@@

jack872184 發表於 2012-10-30 00:08
問題係通5到呢@@

haha~
mth 教育TV 首歌仔~

孖吉 發表於 2012-10-29 23:31
Not on smooth surfaces like water.

Actually, a laser beam is so strong that it can survive severa ...

技術之達人  What is frozen liquid?= = 係指玻璃溶液condense左之後GE form? 幅雷射圖睇得明GE 放心，愚子可教也= =  發表於 昨天 00:33

• 其實係 frozen supercooled liquid, 簡單嚟講，係透明嘅固體囉~
• condensation 係指由 gaseous state 轉成 liquid state, 由 liquid 轉 solid 叫 freezing
• laser 在台灣叫 "雷射"，在香港叫甚至叫 "鐳射" ... 係好懶嘅叫法，因為會同 居禮夫人 發現啲  放射性鐳 混淆，我比較認同國內的叫法 "激光" (其實 "激光" 係由著名科學家 錢學森 命名咖，唔係亂叫咖)
  

jack872184 發表於 2012-10-30 12:51
haha~
mth 教育TV 首歌仔~

嘻嘻~ 係啊，我好鐘意睇ETV架 (小學果時)

孖吉 發表於 2012-10-31 01:35
技術之達人  What is frozen liquid?= = 係指玻璃溶液condense左之後GE form? 幅雷射圖睇得明GE 放心，愚 ...

• forzen supercooled liquid 呢個concept明白~
• condensation同freezing係本人的邏輯問題= =
• 雷射,鐳射,激光就好似  土豆,馬鈴薯,薯仔  既分別姐 +_+
  
  陣間仲有野要問，大家密切留意- -