p6.2 uses and hazards Flashcards
what is background radiation
the level of radiation that we are exposed to every day
what is radioactive contamination and irradiation
contamination - is when a radioactive material gets inside your body or onto your skin. once inside your body you cannot remove it
irradiation - when the radio active material is outside your body, this can travel into your body.
in both cases it causes ionising in the DNA which can cause cancer
how does half life affect what materials are used for medical purposes
radioactive tracers are used to show problems within an organ. if the half life of the tracer is too short then the material will have decayed before reaching the organ
if the half life is too long then the tracer will keep emitting harmful radiation for too long increasing risk of cancer
how is nuclear radiation used for medical purposes
it is used in a “gamma knife” which focuses gamma rays onto a fixed point , most likely a tumour. it rotates around the tumour as to not expose healthy tissue to as much radiation
what is nuclear fission
when an atom splits into fragments and then emits some neutrons
why does nuclear fission occur
it is far more likely to happen when a neutron hits into a nucleus. this causes it to split into two nuclei and a few neutrons. these smaller nuclei may be unstable
where can nuclear fission be used and why
it is used in nuclear power stations to heat water which evaporate and move huge turbines of generators. fission is used because it gives out 1000 times more energy then a combustion reaction would. fission is also used in nuclear powered submarines and in space crafts
what is a chain reaction in terms of nuclear fission
this is when the neutron produced from nuclear fission get absorbed by other atoms and the same process occurs
how is the nuclear fission energy contained within a power plant
around where the fission takes place are materials to absorb the neutrons so that the chain reaction doesn’t happen all at once causing an explosion.
in a nuclear bomb there is no such material so all the energy is transferred to the surroundings
what is nuclear fusion
when two small nuclei join together to make a larger one. this results in large amount of energy being released.
where does nuclear fusion take place and why does it only occur there
it takes place within the sun, the conditions are right in the sun because of the intense heat. this means the atoms are traveling fast enough to overcome the forces of repellents between the protons
where does energy come from in nuclear fusion
the energy comes from a tiny piece of the reactants that have been converted into energy.
what is the equation used to work out energy produced in the nuclear reaction
energy (J) = change in mass (kg) X speed of light ^2(m/s)
E = m X c^2
