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Optics Refraction of light by Prisms The word "prism" usually means a triangular piece of glass or plastic. Deviation by a Prism
i) the angle A of the prism ii) the angle of incidence at the face of the prism iii) the refractive index of the prism material
Dispersion by a Prism Different wavelengths of light travel at different speeds through glass (and other transparent media). Hence, the refractive index is different for different wavelengths (or colours) of light.
In the diagram above
If db is deviation for blue light and dr
is deviation for red light then the angle of dispersion
Equilateral prisms can be used to produce a spectrum. If white light is passed through such a prism, the result is called a continuous spectrum as all the colours are visible.
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is called the angle of
dispersion.