The wavelength (λ) of the wave is the distance from one wave peak
to the next. The frequency (υ) of a wave is simply the number of wave
peaks that pass by a given point per unit time, expressed in units of
reciprocal seconds (1/s or s–1). The relation between these quantities is
given by
λα 1/υ or c = υλ
• Can we apply this equation to a sound wave?
Yes. It is a universal relationship and applies to all waves. As the
frequency increases, the wavelength becomes smaller.
Electromagnetic waves can have a wide variety of frequencies. The
entire range of electromagnetic wave frequencies is known as the
electromagnetic spectrum.
The familiar example of the visible spectrum in nature is the formation
of a rainbow.
Each colour in a rainbow is characterized by a specified wavelength
from red (higher wavelength) to violet (shorter wavelength). These colours
(wavelengths), that the human naked eye is sensitive to, are called visible
light. The range of wavelengths covering red colour to violet colour is
called the visible spectrum.
• Are there any other wavelengths of light other than visible spectrum?
Electrognetic spectrum
Electromagnetic waves can have a wide variety of wavelengths. The
entire range of wavelengths is known as the electromagnetic spectrum.
The electromagnetic spectrum consists of a continuous range of
wavelengths of gamma rays at the shorter wavelength to radio waves at the
longer wavelength. But our eyes are sensitive only to visible light.
