Radiation Flashcards
definition of radioactive decay
the process of a nucleus becoming more stable in its configuration through alpha, beta or gamma decay
Describe the relationship between strong force and electromagnetic force in an unstable nuclei
the are very closely balanced
describe the relationship between strong force and electromagnetic force in a stable nuclei
strong force is greater than electromagnetic force
what emission will a nuclei thats too large produce?
alpha decay
what emission will a nuclei with too many protons produce?
b+
what emission will a nuclei with too many neutrons produce
b-
describe b decay
(interaction, exchange particle, impact)
weak interaction where a w boson moves from an unstable nuclei to stable products
lessons the impact of the electromagnetic force and increases strong force
describe a decay
( interaction, exchange particle, impact)
strong interaction, gluon, decreases radius of nuclei increasing strong force ( diameter within range of strong force)
describe the concept of entropy
inherently unstable systems want to go to a state of lower potential energy (more stable)
describe the concept of quantum tunnelling
random quantum vacuum fluctuations are theorised to promote the nucleus relaxing to a lower state
how can you identify which decay is occurring
by using penetrating power or absorption by different materials
describe a radiation
(charge, elements, ionising, range, deflection)
+2 charge, 4mu mass
Occurs to large elements
strong interaction, gluon exchange particle
most ionising
stoped by paper / skin
deflected to -, south pole
describe b radiation
( charge, ionising, range, deflection)
-1 or +1 charge, 1mu
weak interaction, w boson, slow
stoped by aluminium
less ionising than alpha, more penetrating
deflected to +/ north pole
deflected more as has a greater specific charge
describe gamma rays
least ionising, most penetrating
no mass no charge no deflection
10cm lead
doesnt ever stop just blends with background radiation
name and explain safety precautions for experiment with radiation
-handle with tongs, use gloves, place in holder to prevent contamination
keep far away from source, little time as possible, shielding using concrete barriers or lead plate to prevent irradiation
lead lined container
inlock room
gasses, powders, liquids in sealed containers
name sources of background radiation
air, ground and buildings, cosmic radiation, living things, artificial radiation (medicine, industrial sources)
why would you spend a long time measuring background radiation
reduce percentage uncertainty as it is a random process
difference between gamma radiation and visible light
gamma photons have more energy (higher frequency) than light and therefore more ionising
describe the inverse square law
gamma radiation becomes less intense as you move away from it as area it covers increases (exponential decay)
Definition of intensity and unit
radiation energy passing through a unit area per second W/m^2
derive the equation for corrected intensity using
area of a sphere = 4pie r^2
number of photons emitted =n
energy of each photon = hf
count due to background radiation = c
pic
assumptions made while investigating inverse square law
gamma source is placed in a vacuum so not ionised by air
gamma source emits isotropically
no background radiation contributing to intensity
what is a Becquerel?
number of radioactive particles produced per second
unit of activity . s-1
what is a unit Gray?
how much energy is deposed into mass via ionising radiation
1 joule of such energy per kilo
