Geometric Optics
Prism Spectroscope
   
       
    Date : July 2016
Author : Alexandre April, Mathieu Riopel and Olivier Tardif-Paradis
College : Cégep Garneau
Length : 3 hrs
Related concept(s) : Refractive index, dispersion, refraction, total internal reflection, image formation, thin lenses, focal planes, principal ray
    In this activity, the students will design a prism spectroscope. To do this, they will first analyse the instrument as an imaging system (the spectral lines spread by the spectroscope correspond to images from the entry slot projected on an observation screen). Then the students will be required (given Cauchy’s equation and the definition of the Abbe number in the boxes) to choose the appropriate prism to use for their spectroscope (choice of glass and edge angle). Finally, they will calibrate their spectroscope before using it to determine the wavelengths of the absorption lines that correspond to the visible spectrum of hydrogen.