How is the wavelength of monochromatic light measured

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Homework Help Overview

The discussion revolves around measuring the wavelength of monochromatic light using diffraction grating and a spectrometer, focusing on the principles and mechanisms involved in these methods.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the use of the diffraction grating formula dsinθ = nλ for measuring wavelength, questioning its correctness and exploring the role of the spectrometer in this context.

Discussion Status

Some participants confirm the correctness of the diffraction grating approach and provide additional details about the spectrometer's components and functionality, indicating a productive exchange of information.

Contextual Notes

Participants are examining the accuracy and setup of the instruments involved, with a focus on the assumptions related to the incident beam and measurement techniques.

franklinear
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how is the wavelength of monochromatic light measured by using diffraction grating and spectometer?
 
Last edited:
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What have you found out so far?
 


Using diffraction grating, when incident parallel beam is at normal incidence, then emergent parallel beams are seen in directions such that
dsinθ = nλ

by considering the spacing of grating, and the order of the diffracted beams as well as the angle of diffracted beams to the normal, the wavelength may be measured.

Is it Correct?

What about spectrometer?
 


Hello franklinear,yes it is correct.A spectrometer is an optical instrument that can be used to make measurements of the type you described with a high degree of accuracy.There is a collimator which can be adjusted to produce the parallel incident beam,a table on which to place the grating and a telescope which can be adjusted to focus the emergent beams.The table and telescope can be rotated and and there is a vernier scale to measure the angles.
 
Last edited:

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