Question

Define/Explain the following.
1. Spectrum
2. Dispersion
3. Persistence of vision
4. Cataract

Answer 1

1. Spectrum: The whole range of colours, visible during dispersion, with which white light is formed is called spectrum.
2. Dispersion: The phenomenon of splitting of white light into its constituent colours is called dispersion.
3. Persistence of vision: The phenomenon of the eye where an afterimage is retained, but only for a short period of time, after the removal of the object.
4. Cataract: A condition in which the lens of the eye becomes opaque or cloudy resulting in blurred or dimmed vision.