Radioactivity and Particles Flashcards
what is activity measured in?
radiation emitted per second
Bq- becquerel
what is an isotope?
an atom with the same number of protons but different number of neutrons
what is atomic number?
number of protons in a nucleus
what is mass number?
number of nucleons (protons+neutrons) in a nucleus
what is alpha, beta particles and gamma rays?
ionising radiation emitted from an unstable nuclei in a ransom process
what is ionising radiation?
radiation that can ionise another atom (high energy)
what are the dangers of ionising radiation?
could mutate the DNA inside the cells which could go on to causing cancer
what is the nature and the relative charge of alpha particles?
2 protons + 2 neutrons
charge=+2
what is the nature and relative charge of beta particles?
fast moving electron
charge=-1
what is the nature and the relative charge of gamma rays?
electromagnetic wave
charge=0
what is the penetrating power of alpha, beta and gamma?
alpha-low
beta-medium
gamma-high
what is the ionising power of alpha, beta and gamma?
alpha-high
beta-medium
gamma-low
what is an absorber for alpha?
thin paper
what is an absorber for beta?
aluminium
what is an absorber for gamma?
thick lead/ concrete
what is ionising power?
This is ability of the radiation to cause another atom to gain or lose electrons. When this happens the radiation is absorbed
what is penetrating power?
This is the ability of the radiation to travel through a material without being absorbed.
what can detect ionising radiation?
Geiger Muller tube and the counter to record how many times the radiation was detected
what can detect ionising radiation? 2
photographic plates
what is background radiation?
radiation that is around us all the time
what is background radiation made of?
-gas from the ground-50% radon gas
-food+drink
-cosmic rays
-building + the ground
-artificial sources (human technologies)
what is half life?
the average time taken for half of unstable nuclei to decay
what are the uses of radioactivity in industry and medicine?
smoke detectors
manufacture of aluminium foil
radioactive tracers
medical tracers
carbon dating
what is contaminated?
radioactive source inside the object, this can decay and emit radiation
what is irradiated?
radiation passes through it
-when happens kills bacteria (sterilise)
what are the dangers of ionising radiation?
mutations of living organisms
cell+tissue damage
problems with disposal of radioactive waste
what is fission?
The nucleus is very large and unstable then it can undergo fission.This is where the nucleus split into two nuclei
what elements does fission occur for?
uranium
polonium
describe the process of fission
-slow moving neutron which is absorbed by uranium-235, creating uranium-236 (very unstable)
- the nucleus splits into 2 daughter nuclei and usually 2 or 3 neutrons and lots of energy
what type of energy is released during fission?
the energy released as kinetic energy
lots of kinetic energy then transfers to thermal energy
what is a chain reaction?
where the product from one reaction go to become the reactant of the next reaction
what is a runaway reaction?
when more and more product is created, causing more and more reactions per second, also producing more and more energy per second
-it’s when more than1 neutron is released and each of there could cause more fission
dangers of fission
-runaway reaction, as there is huge amounts of energy released that could cause and explosion
-daughter nuclei that are released are unstable, which decay emitting alpha beta or gamma, which then damages cells and causes cancer
what is the function of the control rods?
control the reaction by absorbing neutrons ( made of boron)
what is the function of the moderator?
designed to slow down the neutrons which keeps the reaction going
what is the function of the shielding around the nuclear reactor?
made of thick concrete which absorbs alpha and beta and reduces gamma to safe levels
what is the function of the shielding around the nuclear reactor?
made of thick concrete which absorbs alpha and beta and reduces gamma to safe levels
what is the function of a coolant?
water
reduces the temperature of the reactor by transferring the heat away
