The Rayleigh Criterion and the Wavelength of Light

  • Thread starter Thread starter Alt+F4
  • Start date Start date
  • Tags Tags
    Formula Power
AI Thread Summary
The discussion focuses on calculating the wavelength of light emitted from a car's taillights using the Rayleigh Criterion. The relevant formula involves the index of refraction, wavelength, and distance, with a key factor of 1.22 for the limiting angle of resolution. Participants are trying to determine the correct distance to use in the calculations, with one suggesting 13.5 km instead of 14.1 km. The conversation emphasizes the need to find the limiting angle to proceed with the wavelength calculation. Overall, the thread highlights the application of diffraction principles in determining light wavelengths.
Alt+F4
Messages
305
Reaction score
0
(b) A car passes you on the highway and you notice the taillights of the car are 1.16 m apart. Assume that the pupils of your eyes have a diameter of 7.2 mm and index of refraction of 1.36. Given that the car is 14.1 km away when the taillights appear to merge into a single spot of light because of the effects of diffraction, what wavelength of light does the car emit from its taillights (what would the wavelength be in vacuum)?


Okay so i know the formula is

Theta = Index of Refraction* Wavelength / Distance

How do i find the limiting angle of resolution in order to get the wavelenght
 
Physics news on Phys.org
Alt+F4 said:
(b) A car passes you on the highway and you notice the taillights of the car are 1.16 m apart. Assume that the pupils of your eyes have a diameter of 7.2 mm and index of refraction of 1.36. Given that the car is 14.1 km away when the taillights appear to merge into a single spot of light because of the effects of diffraction, what wavelength of light does the car emit from its taillights (what would the wavelength be in vacuum)?


Okay so i know the formula is

Theta = Index of Refraction* Wavelength / Distance

How do i find the limiting angle of resolution in order to get the wavelenght
You want to be using the "Rayleigh Criterion". It's the one with the factor of 1.22 in it.
 
Chi Meson said:
You want to be using the "Rayleigh Criterion". It's the one with the factor of 1.22 in it.
ok but then Distance would be 13.5 Km and what is the limiting angle?

(1.22)(X) / (7.2/1000) = ?
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top