How to Calculate Wavelength

Wavelength

Ripples in water, sound traveling in air, and coordinated vibrations of objects are examples of waves you have probably encountered in your life. A good way to visualize a wave is to insert the end of a pencil into a container of still water. The surface of the water is disturbed, producing ripples, or waves.

Electromagnetic waves are special waves, such as light, radio waves, microwaves, and x-rays, that do not require a medium for propagation. We cannot see or hear these waves, but they exist in nature and in many of the products we use every day.

Regardless of the kind, every wave has a wavelength. Wavelength is the distance between two successive like points on a wave. Some examples are the distance between two adjacent peaks or two adjacent valleys. A peak is the highest point of a wave and a valley is the lowest point of a wave. Stated another way, wavelength is the time required to complete one full cycle of the wave.

Wavelength depends on two other important parameters:

1. Wave Speed

The rate at which the wave moves through the medium of propagation. Wave speed is dependent upon the medium of propagation. For example, water ripples travel through the water. Electromagnetic waves usually travel through the air, as do sound waves. Vibrations on a piano string travel through the string. The wave speed is different for all of these because the medium in which the wave propagates is different.

2. Frequency

The number of wave cycles passing a point per unit time. Stated another way, it is the number of oscillations per second in the wave. A higher frequency means a shorter wavelength, and a shorter wavelength means a higher frequency. This leads us to the relationship between wave speed, frequency, and wavelength.

Calculating Wavelength

The speed of the wave equals the number of cycles passing a point each second multiplied by the cycle length.

Mathematically stated: wave speed = cycles per second x cycle length