A prism is the instrument used to break white light into a rainbow by refracting light at different angles depending on its wavelength.
A prism cannot be used to name an ordered pair.
screw gauge
It is named after the type of prism used in the instrument. A constant deviation prism has the property that the angle between light entering the prism (the incident light) and light exiting the prism (the emergent light) is always the same, no matter what the angle of the incident light to the prism.
Rheostat is the name of an instrument used to vary electrical resistance.
Thin layers
They used thin hollow logs as long flutes. They also decorated them.
A Plectrum
A prism is commonly used to break up white light into its spectrum. White light is composed of different wavelengths, each corresponding to a different color. When white light passes through a prism, it is refracted, causing the different wavelengths to separate and create a spectrum of colors.
syringe
Timepieces.
Plectrum