Nuclear Decay 3.5 Flashcards
define nuclear decay?
process by which nucleus of a atom loses energy by emitting radiation.
Define nuclear radiation?
is the emission of energy in the form of waves or particles
define alpha decay?
is a nuclear decay by the emission of a particle (2 protons and 2 neutrons)
define beta decay?
nuclear decay by the emission of an electron or positron.
define gamma decay?
nuclear decay by the emission of a photon.
alpha particle range
3cm of air, 0.02mm of glass
beta particle range
1 m of air, 0.5mm aluminium
gamma particle range
500m of air, 5cm of lead
define alpha radiation
The most weakest penetrating type of nuclear radiation (consists of a helium nuclei)
Define Beta radiation
Has a more penetrating type of alpha radiation(consists of electrons / positrons)
Define Gamma radiation
Most penetrating type of radiation (consists of high energy photons)
Define the range of nuclear radiation
distance it travels before being absorbed.
What does the penetrating power of radiation depends on?
Their energy (Greater their energy greater their range)
how does the density of the material affect radiation?
denser the material the better for absorption.
Gamma rays interaction with electrons.
- gamma rays only are affected by atomic electron
- they lose all their energy in one interaction.
define background radiation?
Nuclear radiation which is detected in the absence of the source under investigation.
If the path is circular for a particle radius of the circular path is given by the equation
radius = momentum / charge X flux density.
define the Activity of a radio active source.
number of radioactive decays per unit time
define the decay constant?
is the fraction of the atoms of a radioactive nuclide which decay per unit time.
equation for activity.
Activity = decay constant / no. of molecules
define half life?
time taken for the no. of nuclei of a radioactive nuclide to halve
equation of activity
Activity = Initial Activity E ^-decay constant X time
Define Time constant
time taken for the activity to decrease by a factor of 1/ee
Equation for time constant
Time = 1 / decay constant
half life equation.
Half life / ln(2) = 1 / decay constant