Quick Optics Question on Gratings (Small calculation)

  • Context: High School 
  • Thread starter Thread starter _Mayday_
  • Start date Start date
  • Tags Tags
    Calculation Optics
Click For Summary

Discussion Overview

The discussion revolves around calculating the distance between grooves in a diffraction grating with 3,000 slits per mm and exploring the application of the grating formula to determine wavelengths. Participants also share experimental observations related to sodium lamp emissions.

Discussion Character

  • Technical explanation, Experimental/applied, Conceptual clarification

Main Points Raised

  • One participant suggests that the distance between grooves can be calculated as 1 mm divided by 3,000 slits, leading to a value of approximately 3.33x10^-4 mm.
  • Another participant confirms the calculation and reiterates the distance between grooves as 1/3000 mm.
  • A participant questions whether the units for the wavelength in the formula n λ = d sin(θ) should match the units used for d, suggesting that converting to nanometers might be more convenient.
  • One participant shares their experimental results using a sodium lamp and spectrometer, noting difficulty in finding reliable wavelength sources for comparison.
  • A participant mentions observing an additional blue line in their results and expresses uncertainty about the accuracy of their measurement for the orange line, which they calculated as 5.7x10^-5 mm.

Areas of Agreement / Disagreement

Participants generally agree on the method for calculating the distance between grooves, but there is uncertainty regarding the accuracy of experimental results and the interpretation of observed spectral lines.

Contextual Notes

Participants express uncertainty about the accuracy of their experimental measurements and the reliability of wavelength sources for comparison.

_Mayday_
Messages
808
Reaction score
0
Hey,

Well, just a quick question, if a grating had 3,000 slits per mm, what would the distance between groves be? Is it 1mm/3,000 which would give me the grove distance?
 
Science news on Phys.org
So 1/3000 = 3.33x10^-4 is the distance between gooves?
 
CrawfordK said:
Is it 1mm/3,000 which would give me the grove distance?
Sounds right to me.

CrawfordK said:
So 1/3000 = 3.33x10^-4 is the distance between gooves?
In mm.
 
^ When using using the formula [tex]n \lambda = d \sin(\theta)[/tex] trying to find the wavelength would I use it in mm?

I've basically conducted an experiment, using a sodium lamp and spectrometer, and want to see how accurate it is by comparing my results with an online result, but am having trouble finding a source that tells me the wavelengths, that I can compare to with my results.
 
_Mayday_ said:
^ When using using the formula [tex]n \lambda = d \sin(\theta)[/tex] trying to find the wavelength would I use it in mm?
When using that formula, the wavelength will have whatever units "d" has. You can always convert it to more convenient units, such as nm.

This might help: http://hyperphysics.phy-astr.gsu.edu/Hbase/quantum/sodium.html#c2"
 
Last edited by a moderator:
I swear I saw a blue line as well though? For the orange line i got 5.7x10^-5 mm, i don't know hwo accurate that is.
 

Similar threads

Undergrad How to couple light from a very small source into spectrometer?
  • · Replies 10 ·
Replies
10
Views
2K
Graduate Calculating the optical depth of an inhomogeous gas
  • · Replies 1 ·
Replies
1
Views
3K
Diffraction pattern from a grating
  • · Replies 3 ·
Replies
3
Views
1K
Graduate The coherence length is much longer than the manufacturer claims
  • · Replies 10 ·
Replies
10
Views
3K
High School Calculating the distance between the optical center and focal length
  • · Replies 1 ·
Replies
1
Views
4K
Undergrad On 'A Quarter Waveplate (QWP) rotated between 2 Polarisers'
  • · Replies 5 ·
Replies
5
Views
3K
Undergrad Question on Optical Systems and Lenses
  • · Replies 1 ·
Replies
1
Views
1K
Undergrad Problem with Diffraction Grating Equation (results do not match theory)
  • · Replies 1 ·
Replies
1
Views
3K
Undergrad Single Slit and Diffraction Grating Formulas
  • · Replies 6 ·
Replies
6
Views
9K
High School Converting Lux to W/m^2 for Solar Radiation Measurement
  • · Replies 9 ·
Replies
9
Views
11K