The decibel scale is a compressed scale of measurement. The least intense sound that can be heard has an intensity of zero decibels. A sound with 10 times the energy is rated at 10 decibels. A sound with 100 times as much energy as the 0 dB sound is rated at 20 dB. Ordinary human whisper is about 20 dB. A conversation is about 60 dB. Sound at 120 dB becomes painful - jet engine noise. A rocket blasting off at about 100 yards has an intensity of about 180 dB, very loud and very painful.
Light is the visible spectrum portion of electromagnetic waves.
Red light is the lowest frequency of light and violet is the highest frequency. I V Light spectrum of colors visible by unaided human eye. The electromagnetic spectrum is a continuum of all electromagnetic waves arranged according to frequency and wavelength. A new theory about light and color which combines elements of Goethe's Theory of Colors and Maxwell's electromagnetic wave theory. The symbol h is called Plank's constant and is a number we use as a multiplier of frequency to calculate the amount of energy in a quantum.