Frequency and wavelength converter. Wavelength

Wavelength is the distance between two adjacent points that oscillate in the same phase; Typically, the concept of "wavelength" is associated with the electromagnetic spectrum. The method for calculating the wavelength depends on this information. Use the basic formula if the speed and frequency of the wave are known. If you need to calculate the wavelength of light from a known photon energy, use the appropriate formula.

Steps

Part 1

Calculating wavelength from known speed and frequency

    Use the formula to calculate the wavelength. To find the wavelength, divide the speed of the wave by the frequency. Formula: λ = v f (\displaystyle \lambda =(\frac (v)(f)))

    Use appropriate units of measurement. Speed ​​is measured in metric units, such as kilometers per hour (km/h), meters per second (m/s), and so on (in some countries, speed is measured in the imperial system, such as miles per hour). Wavelength is measured in nanometers, meters, millimeters and so on. Frequency is usually measured in Hertz (Hz).

    • The units of measurement of the final result must correspond to the units of measurement of the source data.
    • If the frequency is given in kilohertz (kHz), or the wave speed is in kilometers per second (km/s), convert the given values ​​to hertz (10 kHz = 10000 Hz) and to meters per second (m/s).

  1. Plug the known values ​​into the formula and find the wavelength. Substitute the values ​​of wave speed and frequency into the given formula. Dividing speed by frequency gives you wavelength.

    Use the formula provided to calculate the speed or frequency. The formula can be rewritten in another form and calculate the speed or frequency if the wavelength is given. To find the speed from a known frequency and wavelength, use the formula: v = λ f (\displaystyle v=(\frac (\lambda )(f))). To find the frequency from a known speed and wavelength, use the formula: f = v λ (\displaystyle f=(\frac (v)(\lambda ))).

    Part 2

    Calculating wavelength from known photon energy

    1. Calculate the wavelength using the formula for calculating photon energy. Formula for calculating photon energy: E = h c λ (\displaystyle E=(\frac (hc)(\lambda ))), Where E (\displaystyle E)– photon energy, measured in joules (J), h (\displaystyle h)– Planck’s constant equal to 6.626 x 10 -34 J∙s, c (\displaystyle c)– speed of light in vacuum, equal to 3 x 10 8 m/s, λ (\displaystyle \lambda)– wavelength, measured in meters.

      • In the problem, the photon energy will be given.

    2. Rewrite the given formula to find the wavelength. To do this, perform a series of mathematical operations. Multiply both sides of the formula by the wavelength, and then divide both sides by the energy; you will get the formula: λ = h c E (\displaystyle \lambda =(\frac (hc)(E))). If the photon energy is known, the wavelength of the light can be calculated.

Wavelength

Examples

Approximately, with an error of about 0.07%, you can calculate the radio wavelength as follows: 300 divided by the frequency in megahertz, we get the wavelength in meters, for example for 80 Hz, the wavelength is 3750 kilometers, for 89 MHz - 3.37 meters, for 2 .4 GHz - 12.5 cm.

The exact formula for calculating the wavelength of electromagnetic radiation in a vacuum is:

where is the speed of light, equal in the International System of Units (SI) to 299,792,458 m/s exactly.

To determine the wavelength of electromagnetic radiation in any medium, use the formula:

where is the refractive index of the medium for radiation with a given frequency.

Notes

Literature


Wikimedia Foundation. 2010.

See what “Wavelength” is in other dictionaries:

    The distance between the two closest points of a harmonic wave that are in the same phase. Wavelength λ = vT, where T is the oscillation period, ? phase speed of the wave. * * * WAVELENGTH WAVELENGTH, the distance between the two nearest points... ... encyclopedic Dictionary

    wavelength- (λ) The distance by which the surface of an equal phase wave moves during one period of oscillation. [GOST 7601 78] wavelength The distance traveled by an elastic wave in a time equal to one full period of oscillation. )

mob_info