作者little1315 (~花開的時令到嘍~)
看板Chemistry
標題[學習] 物化
時間Wed Mar 5 00:45:01 2008
The DVD player uses shorter wavelength lasers
to read the digital pits in the rings, thus increasung
the accuracy of reading the more densely packed data.
If the laser emits red light of wave length 635 nm.
How many photons does it emit every second if
it's power is 0.05 W
我知道
Watt = J / sec
但不知道怎下手 >"<
有人這樣解
E = hc/波長 = 6.602 * 10^-34 * 3*10^8 / (635*10^-9)
所以 E = 3.1 * 10^-19
0.05 / (3.1 * 10^-19) = 1.6*10^17個
有人可以解釋最後一行為什麼嗎？
AND
A mode-locked laser produces pulses at a repetition
rate of 100 MHz. If each pulse is 10 fs in duration
and has a pulse energy of 10 nJ.
What is the average power ?
這題小弟也無頭緒
一樣有高手這樣解
100M pulse
所以 100 * 10^6 * 10 nJ / 1 sec = 1 W
請問有高手可以解說一下嗎？
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1F：推 a88405971:就是1.6*10^17個光子的總能量=0.05 03/05 00:48
※ 編輯: little1315 來自: 218.164.81.130 (03/05 01:06)
2F：→ little1315:謝謝一樓 小的瞭解了 ^^ 03/05 22:43