When first discovered α, β and γ radioactivity were referred to as α−rays, β-rays and γ- rays. now we refer to α-particles and β-particles, but still use the term γ-rays. what type of particles are α and β commonly known as? what type of ray is γ commonly known as? what are the signs of the charges on the three forms of radiation?

1. Helium nucleus and electron/positron

- An decay is a decay in which an particle is produced.

An particle consists of 2 protons and 2 neutrons: therefore, in an alpha-decay, the nucleus loses 2 units of atomic number (number of protons) and 2 units of mass number (sum of protons+neutrons).

The alpha-particle consists of 2 protons of 2 neutrons: so it corresponds to a nucleus of helium, which consists exactly of 2 protons and 2 neutrons.

- There are two types of decay:

-- In the decay, a neutron decays into a proton emitting a fast-moving electron and an anti-neutrino:

and the particle in this case is the electron

--  In the decay, a proton decays into a neutron, emitting a fast-moving positron and a neutrino:

and the particle in this case is the positron.

2) Gamma ray

A decay occurs when an unstable (excited state) nucleus decays into a more stable state. In this case, there are no changes in the structure of the nucleus, but energy is released in the form of a photon:

where the wavelength of this photon usually falls in the part of the electromagnetic spectrum corresponding to the gamma ray region.

So, the ray is commonly known as gamma radiation.

3)

The sign of the three forms of radiation are the following:

- particle: it consists of 2 protons (each of them carrying a positive charge of +e) and 2 neutrons (uncharged), so the total charge is

Q = +e +e = +2e

- particle: in case of radiation, the particle is an electron, so it carries a charge of

Q = -e

in case of radiation, the particle is a positron, so it carries a charge of

Q = +e

- radiation: the radiation consists of a photon, and the photon has no charge, so the charge in this case is

Q = 0

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