Chapter 1 - Matter and radiation Flashcards
What is a nucleon?
A proton or a neutron in the nucleus.
What is a nuclide?
Different types of nucleus of the same element but with different numbers of nucleons.
What is the specific charge of a particle?
Its charge to mass ratio.
What is the strong nuclear force?
A force which keeps the protons and neutrons together by overcoming the electrostatic force of repulsion between the protons in the nucleus and also prevents them from pushing into each other.
What is the range of the strong nuclear force?
3fm to 0.5fm attractive force,
<0.5fm repulsive force
Describe alpha radiation.
Alpha radiation consists of alpha particles which each compromise two protons and two neutrons.
The product nucleus belongs to a different element.
It tends to occur in nuclei that are too large for the strong nuclear force to keep them stable.
Describe beta radiation.
Beta- decay:
When a nucleus has too many neutrons, a neutron changes into a proton causing the emission of a beta particle (fast moving electron) and an antineutrino particle.
Beta+ decay:
When a nucleus has too many protons, a proton changes into a neutron causing the emission of a positron and a neutrino.
The product nucleus belongs to a different element.
What is gamma radiation?
Electromagnetic radiation emitted by an unstable nucleus. It is emitted by a nucleus with too much energy, following an alpha or beta emission.
Electromagnetic waves are emitted by a charged particle when it loses energy. This can happen when:
a fast-moving electron is stopped or slows down or changes direction.
an electron in a shell of an atom moves to a different shell of lower energy.
What is a photon?
A short burst (packet) of electromagnetic waves.
What is the photoelectric effect?
Emission of electrons from a metal surface when the surface is illuminated by light of frequency greater than a minimum value known as the threshold frequency.
What is 1eV in joules?
1.60x10-19J
What is 1MeV in joules?
1.60x10-13J
Describe the process of particle-antiparticle annihilation.
A particle and its corresponding antiparticle meet and their mass, including rest mass, is all converted into radiation energy so that energy is conserved. A pair of photons of equal energy are produced and travel in opposite directions to ensure a total momentum of 0 after the collision.
What are the exchange particles of the weak nuclear force, strong nuclear force and electromagnetic interactions?
W boson - Weak nuclear force
Virtual photon - Electromagnetic
Pion - Strong interaction
