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# Wavelength of Light

Top
 Sub Topics The wavelength is nothing but the length of a wave. The wavelength of light will be so small that it is expressed in nanometers (nm). In the modern physics its accepted that the light has a dual nature. Sometimes it acts as mass less particles and the other times as waves. If light is taken as a wave, the visible light has several colors having its own wavelength slightly varying from other that determines other properties of the light wave like frequency, speed etc. Wavelength of a wave.

## Wavelength of Light Formula

The light wave has its own frequency, wavelength and speed. To calculate the wavelength of light, use formula
$\lambda$ = $\frac{c}{f}$

Since the speed of light is constant (c = 3 $\times$ 108 m/s).
Hence, the formula is

$\lambda$ = $\frac{3 \times 10^8\ m/s}{f}$where f is the frequency of light.

The frequency varies from violet to red. Hence the wavelength varies depending on its frequency.

## Wavelength of Visible Light

The visible spectrum of light comprises of following colors: Violet, Indigo, Blue, Green, Yellow, Orange, Red has known as VIBGYOR. It corresponds to the wavelength range of 400-700 nm. It varies from shortest to longest wavelength. The white light is composed of all these colors present in the visible spectrum.

 Light Color Wavelength Violet 390 - 420 Indigo 420 - 455 Blue 455 - 492 Green 492 - 577 Yellow 577 - 597 Orange 597 - 622 Red 622 - 780

## How to calculate wavelength of light?

Lets see some examples on how to calculate the wavelength of light:

### Solved Examples

Question 1: A light wave has frequency of 6.23 $\times$ $10^{14}$ Hz. Calculate its wavelength and determine in which color it lies in the spectrum.
Solution:

Given:
Frequency of wave = 6.23 $\times$ $10^{14}$ Hz

The wavelength of light wave is given by,
Wavelength $\lambda$ = $\frac{3 \times 10^8\ m/s}{6.23 \times 10^14}$
= 481 nm

Question 2: Calculate the frequency if the wavelength of wave is 660 nm.
Solution:

Given:
Wavelength of wave $\lambda$ = 660 nm

The frequency of light wave is given by,
Frequency f = $\frac{3 \times 10^8\ m/s}{\lambda}$
= $\frac{3 \times 10^8\ m/s}{660 \times 10^-9\ m}$
= 4.5 $\times$ $10^{14}$ Hz.