N1-03
Demonstrate continuous spectrum using water as the dispersing medium.
The bright point source is used to provide a continuous white light spectrum. Light from the point source is focused by a condenser lens with iris and a 20 cm focal length cylindrical lens onto a slit. A 20 cm focal length convex lens then images the slit onto the screen through a prism consisting of an equilateral triangular plastic box filled with water. The spectrum created has less dispersion than that of a glass prism due to the smaller index of refraction of water. The spectrum of a quartz glass prism is shown at the right above for comparison.

Before showing the demonstration, invite students to predict how the different index of refraction will change the spectrum seen.
OM1, LS1

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