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NICE VIDEO - PLEASE WATCH!

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What is Light? How Faraday Dreamed of Electromagnetic Waves!

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EM Spectrum | Electromagnetic Waves | GCSE Physics (9-1) | kayscience.com

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Problem:

Find the wavelength of orange light with a frequency of 4,8×10¹⁴ Hz.

c = f λ

3 x 108 = 4,8 × 1014 λ

λ = (3 x 108 ) / (4,8×1014 )

λ = 6,2 x 10⁻⁷ m

= 620 nm

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Einstein concluded that electromagnetic radiation behaves as a beam of particles.

These particles are called PHOTONS

Photons have no mass.

Photons do have energy, even though they are massless.

Photons impart their energy to particles like electrons they interact with, and can knock electrons out of place from metal surfaces.

Photons' energy is related to the frequency or wavelength of the radiation according to Planck's law (in this equation):

E = hf

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Watch this video

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The energy of an individual photon (as smallest particle of light or an EM wave) is quantized and is greater for photons of higher frequency.

This relationship is given by Planck's equation:

E = hf

where E is the energy per photon, f is the frequency of the photon, and h is Planck's constant.

Examples:
1.
The frequency of an electromagnetic wave is 6 x 10¹⁶ Hz.
Calculate its wavelength in air. (Use c = 3 x 10⁸ m.s-¹)

2.
Calculate the energy of a photon of red light of wavelength 7,5 x 10⁻⁷m. (use h = 6,63 x 10 -34 J.s)

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EM Waves are generated by "wiggling" an electron - either in an aerial, a conducting material or in a star like the Sun.
Open this simulation to illustrate:
https://phet.colorado.edu/sims/cheerpj/radio-waves/latest/radio-waves.html?simulation=radio-waves