L.K. 發表於 15-4-2008 13:42:00

04 PP1 PHY

完全唔明問咩..冇時間lahelp...

piyopiyo 發表於 15-4-2008 14:07:37

04年?=.=...點解我無印象ge...我前日先做完04 =.=...
1a. magnet... coil,,,,,,,commutator etc.
b. Blades turn -->coil inside turn in the magnetic field --> induced voltage -->current flows through the bulbs and lights up

2a. wavelength x frequency = speed
2b. X... energy lost , amplitude is smaller
2ci. speed = 6x10^3,,,total distance travelled:0.0435m , 乘番 1000,,, 43.5 mm
2cii plot graph 自搞
2ciii. 睇到個graph 就做到,,,
2d. 題目話佢只係用 1個pulse,,,咁照理只有2個 pulse係CRO 度,1個reflected,1個放出去,但呢度有3個pulse, we can conclude that there's a crack inside the wall , the crack reflect the pulse

L.K. 發表於 15-4-2008 14:16:08

turn in 點解???

piyopiyo 發表於 15-4-2008 14:22:21

原帖由 L.K. 於 15-4-2008 14:16 發表 http://www.nakuz.com/bbs/images/common/back.gif
turn in 點解???
成句理解ar []turn in the magnetic field ar []

L.K. 發表於 15-4-2008 14:24:44

回復 4# 的帖子

[] 咁成句點解...[]


仲有點解有crack就會...多左個...?[]

piyopiyo 發表於 15-4-2008 14:32:40

原帖由 L.K. 於 15-4-2008 14:24 發表 http://www.nakuz.com/bbs/images/common/back.gif
[] 咁成句點解...[]


仲有點解有crack就會...多左個...?[]
個coil 係個magnetic field入面轉 []


個crack reflect左個pulse 咪多左個lor[]

L.K. 發表於 15-4-2008 14:36:46

http://www1.nakuz.com/bbs/images/smilies/Tuzki/tk_35.GIF2b. X... energy lost , amplitude is smaller[]
[]
energy lost 左去邊?http://www1.nakuz.com/bbs/images/smilies/Tuzki/tk_35.GIF
http://www1.nakuz.com/bbs/images/smilies/Tuzki/tk_35.GIF
個crack reflect左個pulse 咪多左個lor http://www1.nakuz.com/bbs/images/smilies/Tuzki/tk_35.GIF
http://www1.nakuz.com/bbs/images/smilies/Tuzki/tk_35.GIF
可唔可以用圖解..... http://www1.nakuz.com/bbs/images/smilies/Tuzki/tk_35.GIF

piyopiyo 發表於 15-4-2008 15:13:28

原帖由 L.K. 於 15-4-2008 14:36 發表 http://www.nakuz.com/bbs/images/common/back.gif
http://www1.nakuz.com/bbs/images/smilies/Tuzki/tk_35.GIF2b. X... energy lost , amplitude is smaller[]
[]
energy lost 左去邊?http://www1.nakuz.com/bbs/images/smilies/Tuzki/tk_35.GIF
http: ...
energy lost to surrounding []

係,多左個咪即係crack 左 lor[]

[S]【YU】 發表於 15-4-2008 16:20:32

magnet... coil,,,,,,,commutator etc.
commutator is not required in this application, because the direction of current flow makes no difference.
We need a commutator only when we want to make a DC generator.
So the essential parts should be the coil and magnet only.

b. Blades turn -->coil inside turn in the magnetic field --> induced voltage -->current flows through the bulbs and lights up
Blades is connected to the coil under magnetic field in the motor.
Blades turns --> coil rotates and cuts the magnetic field --> voltage induced inside the coil (by right hand rule)
A complete circuit consisting the coil and the bulb allows current flow --> bulb light up

decrease in amplitide is caused by diffraction of wave, the recevier cannot collect 100% of the transmitted wave.



[ 本帖最後由 【YU】 於 15-4-2008 16:32 編輯 ]

L.K. 發表於 15-4-2008 16:36:03

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原來係咁...
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