This document details an experiment using a spectrometer to determine the apex angle of a prism. It includes observations, readings, and diagrams related to light refraction and reflection, emphasizing the principles of optics and the behavior of light in different. Experiment 3 focuses on determining the refractive index of a glass prism for sodium light using a spectrometer. Spectrometer: An. When a beam of light strikes on the surface of transparent material (Glass, water, quartz crystal etc. ). Switch On/Off Light : Used to switch on/off the light. Place Prism/Remove Prism : This switch used to place the prism on the prism table or remove prism from the prism table. Slit width : Using this slider, width of.