Absorption spectrum of Na using arc lamp, slit and grating.

White light from the carbon arc passes through a slit and is sent through a 19,050 lpi transmission diffraction grating, creating a full spectrum on a projection screen. Step 2: Heat the metallic sodium in the hand-held sodium 'boat' behind the slit and observe the line absorption. Two dark vertical lines will appear in the yellow region of the otherwise continuous spectrum. Note to setup people: The second lens is positioned so that the image of the spectrum is focused on the screen. This insures that the absorption lines are well-focused. The bunsen burner will need to be placed on a lab jack to get the proper height for the flame. Absorption spectrum of Na using arc lamp, slit and grating.