What is the unit of frequency?

The hertz (Hz), which means one cycle per second.

How is frequency related to energy?

For photons, energy equals Planck's constant times frequency, so higher-frequency radiation carries more energy per photon.

PhysicsGCSE, IGCSE & A Level

Frequency is the number of complete waves or oscillations passing a point each second, measured in hertz.

Frequency is the reciprocal of the period, so a wave with a period of

0.02\,\text{s}

has a frequency of

50\,\text{Hz}

It determines pitch for sound and colour for visible light, and it stays constant when a wave moves between media.

f = \dfrac{1}{T}

A pendulum completing

30

swings in

60\,\text{s}

has a frequency of

0.5\,\text{Hz}

Read the axis of an oscilloscope trace carefully — the period comes from the time base, and only then can you invert it for frequency.

What is the unit of frequency?: The hertz (Hz), which means one cycle per second.
How is frequency related to energy?: For photons, energy equals Planck's constant times frequency, so higher-frequency radiation carries more energy per photon.

Wave speed is how fast a wave transfers energy through a medium, equal to frequency multiplied by wavelength.

Refraction is the change in direction of a wave as it crosses a boundary between media, caused by a change in its speed.

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