PURPOSE: Demonstrate absorption spectrum of chlorophyll.
DESCRIPTION: A bright point source with condenser lens and iris is focused by a 10 cm focal length cylindrical convex lens onto a slit, which is in turn focused onto a distant screen by a 20 cm focal length spherical convex lens. A white light spectrum is obtained by inserting an equilateral prism just after the spherical lens. A chlorophyll solution, prepared by smushing up grass in a container of methanol, is placed in the beam just before the slit. The system now shows the absorption spectrum of chlorophyll.
The color of chlorophyll is not a narrow band of green, but rather is achieved by removing the complementary color, magenta, by absorbing some of the red and blue spectrum.
REFERENCES: (PIRA 6F10.56)
EQUIPMENT: Bright point source with condenser lens and iris, 10cm focal length cylindrical convex lens, slit, 20cm spherical convex lens, and prism, with solution of smushed grass in alcohol.
SETUP TIME: 10 min..
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