# Electromagnetic waves question

• selearemus

#### selearemus

based on this picture

if light is made up of little tiny massless particles called photons
what are microwaves made of?
what are infrared waves made of?
what are ultraviolet waves made of?
what are x-ray waves made of?
gamma rays are made of electrons and electrons have mass
so why don't photons have mass?
how can it be that only 1 type of electromagnetic waves have mass?

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if light is made up of little tiny massless particles called photons
what are microwaves made of?
what are infrared waves made of?
what are ultraviolet waves made of?
what are x-ray waves made of?
gamma rays are made of electrons and electrons have mass
so why don't photons have mass?
how can it be that only 1 type of electromagnetic waves have mass?
All electromagnetic waves are made of photons. Gamma rays too. You have been misinformed.

Also, the type of electromagnetic wave (microwave, radiowave etc.) depends on the frequency of the photons. The type of wave is essentially defined by the frequency of the electromagnetic waves, i.e. photons.

Light has mass because it has energy. E = mc^2. Light has no rest mass.

As you accelerate an object it gains mass as you approach the speed of light. If you could reach the speed of light the object's mass becomes infinite (one good reason why that's impossible). If you could accelerate an object that has zero mass to begin with it would have a real quantity of mass at light speed.

Beta rays are made of electrons and positrons, gamma rays are EM.

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All electromagnetic waves are made of photons. Gamma rays too. You have been misinformed.
Wikipedia**
Gamma radiation, also known as gamma rays (denoted as γ), is electromagnetic radiation of high frequency (very short wavelength). They are produced by sub-atomic particle interactions such as electron-positron annihilation, ...

so the electron-positron annihilation produces photons?

so the electron-positron annihilation produces photons?
Yes. But that is different than saying the photons are made of electrons.

Electron-proton interactions can produce visible light photons. Yet those photons are not made of electrons and protons.

Wikipedia**
Gamma radiation, also known as gamma rays (denoted as γ), is electromagnetic radiation of high frequency (very short wavelength). They are produced by sub-atomic particle interactions such as electron-positron annihilation, ...

so the electron-positron annihilation produces photons?
Yup. An electron hitting a positron normally annihilates into two 511 keV-photons.

However, I think the most common reason for gamma radiation is a deexciting nucleus. When an excited nucleus deexcites the deexcitation energy is released in the form of a photon, a gamma ray.