Content

• To step
• Method 1 of 2: The basics
• Method 2 of 2: Calculating the wavelength
• Tips

Wavelength is the distance between peaks and dips in a wave and is usually associated with the electromagnetic spectrum. You can easily find the length of a wave, provided you know the speed and frequency of the wave. If you want to know how to calculate the wavelength, follow the steps below.

To step

Method 1 of 2: The basics

1. Learn the formula for calculating wavelength. To find the wavelength of a wave, divide the wave speed by the frequency of the wave. The formula for calculating the wavelength is: wavelength = wavelength / frequency
   • Wavelength is usually indicated by the Greek letter lambda (λ)
   • Speed ​​is usually indicated by the letter C.
   • Frequency is usually indicated by the letter F.
2. Write down the formula with the correct units. When the wave speed and frequency are expressed in their respective S.I. units - m / s (meters per second) and Hz (Hertz per second), the wavelength should also be indicated in S.I. units, so in meters, or abbreviated m.
3. Enter the known values ​​into the equation. Enter the wave speed and frequency into the equation to calculate the wavelength: Calculate the wavelength of a wave that travels at a speed of 20 m / s and has a frequency of 5 Hz. This is what this looks like:
   • Wavelength = wave speed / frequency
   • λ = C / F
   • λ = (20 m / s) / 5 Hz
4. Solve. Once you have entered all known values, solve the equation. (20 m / s) / 5Hz = 4 m. Λ = 4 m.

Method 2 of 2: Calculating the wavelength

1. Determine the wave speed if the wavelength and frequency are known. If you know the wavelength and frequency of a wave, you enter the values ​​in the formula and change them so that you can solve the wave speed with it. Solve the following problem: Determine the speed of a wave with a frequency of 8 Hz and a wavelength of 16 m. This is how you do this:
   • wavelength (λ) = wavelength (C) / frequency (F)
   • λ = C / F
   • 16 m = C / 8 Hz
   • 128 m / s = C
   • Speed ​​= 128 m / s
2. Determine the wave frequency if the wavelength and speed are known. If you know the wavelength and speed of a wave, all you have to do is use the formula with these values ​​and change the formula to calculate the wave speed. Solve the following problem: Determine the frequency of a wave with a speed of 10 m / s and a wavelength of 5 m. This is how you do this:
   • Wavelength (λ) = Wave Speed ​​(C) / Frequency (F)
   • λ = C / F
   • 5 m = (10 m / s) / F
   • 1/2 Hz = F
   • Frequency = 1/2 Hz
3. Calculate the wavelength of a wave after the wave frequency has doubled. When the frequency of a wave is doubled, its speed remains the same, but the wavelength is cut in half. The wavelength and frequency are inversely related. Here's how you can prove it:
   • The wavelength of a wave is 4 when the wave speed is 20 m / s and the frequency is 5Hz.
   • When the frequency is doubled, it becomes 10 Hz. Apply this to the formula to find the wavelength. Wavelength = (20 m / s) / 10 Hz = 2 m. The wavelength was 4 and becomes 2, or has been cut in half, after the frequency is doubled.

Tips

• If the frequency is stated in Kilohertz or the wave speed in km / s, then you will need to convert these numbers to Hertz and m / s to make it easier.
• Dispersion Equation:
  • L = (gT² / d · pi) (tgh (2 · pi · d / L))
  • d = depth; pi = 3.14159; T = period
  • Solve this iteratively.