PURPOSE: Demonstrate continuous spectrum.

DESCRIPTION: Light from a bright point source is focused by a condenser lens with iris and a 20 cm focal length cylindrical convex lens onto a slit. The slit is focused onto a distant screen by a 10 cm focal length convex spherical lens. The diffraction grating is placed in the beam following the 20 cm convex lens. The zero order white spot and several spectral orders can be seen on each side of the grating, as shown below. Gratings of 2000 lines/inch and 7500 lines/inch are presented with this demonstration; others are available on request.

SUGGESTIONS:

REFERENCES: (PIRA 6D20.20)

EQUIPMENT: Bright point source with condenser lens and iris, 20 cm focal length cylindrical convex lens, precision slit, 20 cm focal length spherical convex lens, and gratings: 2000 lines/inch and 7500 lines/inch.

SETUP TIME: 5 min.