作者little1315 (~花开的时令到喽~)
看板Chemistry
标题[学习] 物化
时间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 >"<
有人这样解
E = hc/波长 = 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个
有人可以解释最後一行为什麽吗？
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 ?
这题小弟也无头绪
一样有高手这样解
100M pulse
所以 100 * 10^6 * 10 nJ / 1 sec = 1 W
请问有高手可以解说一下吗？
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1F：推 a88405971:就是1.6*10^17个光子的总能量=0.05 03/05 00:48
※ 编辑: little1315 来自: 218.164.81.130 (03/05 01:06)
2F：→ little1315:谢谢一楼 小的了解了 ^^ 03/05 22:43