P4 Flashcards
Difference between stable and unstable nuclei
Unstable/ is not always going to stay the same so nucleus will undergo radioactive decay
Stable- will not undergo radioactive decay has stayed the same for millions of years and will stay the same
What is an alpha particle made of
Helium nucleus
Name four types of decay
Alpha
Beta
Gamma
Neutron
What happens when a nucleus emits an a- particle
The mass number decreases by 4
Atomic number decreases by 2
What is a beta particle
Fast moving electrons
What happens when a nucleus emits a B particle
Mass number stays the same
Atomic numbers increases by 1
What is gamma decay
Happens when a nucleus is in an excited state and moves to a lower energy state
They move to a lower energy state to be more stable
What happens when a nucleus emits gamma radiation
The mass and atomic numbers do NOT change
How far can alpha, beta and gamma go before being stopped
Alpha- can’t penetrate paper
Beta- can go through paper, stopped by aluminium
Gamma- can go through paper and aluminium but stopped by lead
Gamma has the longest wavelength and lowest frequency, true or false
FALSE.
Gamma has the shortest wavelength and highest frequency
What is neutron emission, what happens
The emission of a neutron from an unstable nucleus
The mass number decreases by 1
The atomic number stays the same
Is neutron emission good or bad for the body
Bad.
The shedding of excess neutrons makes it dangerous. Free neutrons can penetrate through the body and materials
What is half life
The time it take for the number of nuclei in a sample of the isotope to halve
What is activity of half life measured in
Bequerels
1Bq = 1 decay per second
What is irradication
The process of exposing an object to ionising radiation
What is radioactive contamination
When an object contains radioactive nuclei
An object is contaminated they have radioactive nuclei, this will decay and release ionising decay
Why are gamma rays used on food
They kill bacteria and prolong the shelf life of food
It’s not dangerous to eat food that has has gamma rays used on it, why is that
When a gamma ray passes through food they deposits energy in it, they do not have the power to make the food radio active/ actually contaminate it
