How do you determine frequency if a microwave is 6.0 cm in length?

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electreto05 | College Teacher | (Level 1) Assistant Educator

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Microwaves are electromagnetic waves, whose frequency is between 300 megahertz (MHz) and 300 gigahertz (GHz) and a wavelength in the range of 1 m to 1 mm; therefore the microwave range is included in radio frequency bands.

The speed of a wave is the relationship between the wavelength and the period, that is:

v = λ/T


v, is the wave velocity.

λ, is the wavelength.

T, is the wave period.

As the period is the inverse of the frequency (T = 1/f), then we can write the velocity as follow:

v = λ*f

In the case of electromagnetic waves, the speed (v) is equal to the speed of light in the vacuum (c = 3*10^8 m/s); so that by solving the above equation for the frequency, we have:

f = v/λ

f = (3*10^8)/(6*10^-2)

f = 0.5*10^10 = 5*10^9 Hz = 5 Ghz

So the frequency (f = v/λ) of a microwave of 6.0 cm in length is 5 Ghz.