Avogadro wrote:Here's your question:
The absorption spectra for chlorophyll a and chlorophyll b are shown above. How does this help to explain why leaves appear green?
Almost none of the yellow and green light is absorbed. It is instead reflected and picked up by our eyes, so the leaves appear green.
Correct. Your turn.
Re: Optics B/C
Posted: February 10th, 2017, 7:23 pm
by kenniky
What is the free-spectral range of a Fabry-Perot cavity in air, of length 31 cm, at a wavelength of 1105 nm? also shamelessly stolen from the MIT test, mostly because I don't think their process is right
Re: Optics B/C
Posted: February 13th, 2017, 6:47 pm
by Avogadro
kenniky wrote:What is the free-spectral range of a Fabry-Perot cavity in air, of length 31 cm, at a wavelength of 1105 nm? also shamelessly stolen from the MIT test, mostly because I don't think their process is right
From what I've managed to find on the subject, it looks like it should be wavelength squared over two times the length of the cavity, and we can probably safely ignore the slight difference between refractive index of air and vacuum. Using this, I got a result of 0.0039... nanometers, I think? Not really sure if I did this right.
Re: Optics B/C
Posted: February 13th, 2017, 7:00 pm
by kenniky
Avogadro wrote:
kenniky wrote:What is the free-spectral range of a Fabry-Perot cavity in air, of length 31 cm, at a wavelength of 1105 nm? also shamelessly stolen from the MIT test, mostly because I don't think their process is right
From what I've managed to find on the subject, it looks like it should be wavelength squared over two times the length of the cavity, and we can probably safely ignore the slight difference between refractive index of air and vacuum. Using this, I got a result of 0.0039... nanometers, I think? Not really sure if I did this right.
that's not what I'm getting... check again?
Re: Optics B/C
Posted: February 23rd, 2017, 5:24 pm
by Avogadro
kenniky wrote:
Avogadro wrote:
kenniky wrote:What is the free-spectral range of a Fabry-Perot cavity in air, of length 31 cm, at a wavelength of 1105 nm? also shamelessly stolen from the MIT test, mostly because I don't think their process is right
From what I've managed to find on the subject, it looks like it should be wavelength squared over two times the length of the cavity, and we can probably safely ignore the slight difference between refractive index of air and vacuum. Using this, I got a result of 0.0039... nanometers, I think? Not really sure if I did this right.
that's not what I'm getting... check again?
Well if that didn't work I'm not really sure how to do it... how did you do the calculation?
Re: Optics B/C
Posted: February 23rd, 2017, 5:51 pm
by kenniky
Avogadro wrote:
kenniky wrote:
Avogadro wrote:
From what I've managed to find on the subject, it looks like it should be wavelength squared over two times the length of the cavity, and we can probably safely ignore the slight difference between refractive index of air and vacuum. Using this, I got a result of 0.0039... nanometers, I think? Not really sure if I did this right.
that's not what I'm getting... check again?
Well if that didn't work I'm not really sure how to do it... how did you do the calculation?
Your formula is right but for some reason I'm getting a different result than you did, check your calculation again I think
Re: Optics B/C
Posted: February 23rd, 2017, 6:18 pm
by Avogadro
kenniky wrote:
Avogadro wrote:
kenniky wrote:
that's not what I'm getting... check again?
Well if that didn't work I'm not really sure how to do it... how did you do the calculation?
Your formula is right but for some reason I'm getting a different result than you did, check your calculation again I think
Got 0.00196 nm this time. Sounding better?
Re: Optics B/C
Posted: February 24th, 2017, 7:23 am
by kenniky
Avogadro wrote:
kenniky wrote:
Avogadro wrote:
Well if that didn't work I'm not really sure how to do it... how did you do the calculation?
Your formula is right but for some reason I'm getting a different result than you did, check your calculation again I think
Got 0.00196 nm this time. Sounding better?
Yup, your turn
Re: Optics B/C
Posted: February 24th, 2017, 12:45 pm
by Avogadro
Oh good, I was getting worried there.
White light is passed first through a filter absorbing wavelengths of light around 700 nm, and then through another filter absorbing wavelengths of light around 450 nm. It then hits a (yellow) lemon. Assuming no other light is present, what color does the lemon appear?
