super fluids

7/24/2019 Super Fluids

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Super fuidsSuper fuids


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There are our phases o matter :There are our phases o matter :

solid, liquid,gas,and plasmasolid, liquid,gas,and plasma

they all conduct electricity and heat but itthey all conduct electricity and heat but itdepends on density so the conduction isdepends on density so the conduction is

excellent at solids and it is good at liquidsexcellent at solids and it is good at liquids

and it is very bad at gasesand it is very bad at gases

fuids are materials that can fow and takefuids are materials that can fow and take

the shape o the container and havethe shape o the container and have

properties such as viscosity and suraceproperties such as viscosity and suracetensiontension


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Super fuidsSuper fuids

They are fuids that conduct electricityThey are fuids that conduct electricity

well because the resistance becomeswell because the resistance becomes

zerozero


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hat is its causehat is its cause??

Superconductivity is due to e!ectiveSuperconductivity is due to e!ectiveattraction between conducting electronsattraction between conducting electrons

"ecause two electrons experience a repulsive"ecause two electrons experience a repulsive

coulomb orce , there must be an additionalcoulomb orce , there must be an additionalattractive orce between two electrons byattractive orce between two electrons bytwo waystwo ways::

11((at low temperatureat low temperature

hen we decrease temperature , the internalhen we decrease temperature , the internalenergy and the kinetic energy o moleculesenergy and the kinetic energy o moleculesdecrease in order to ease passing odecrease in order to ease passing ochargescharges


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the critical temperaturethe critical temperature

is the temperature whom the fuid temperatureis the temperature whom the fuid temperaturedoes not exceed , the resistance becomes zerodoes not exceed , the resistance becomes zero


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22((hen they are sub#ected tohen they are sub#ected to

high pressurehigh pressurebecause when the pressure increases, the volumebecause when the pressure increases, the volume

decreases and when the volume decreases ,thedecreases and when the volume decreases ,the

density increases$ %nd when the density increases,density increases$ %nd when the density increases,

the conductivity increasesthe conductivity increases


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however, there are many superconductors materials ,some ohowever, there are many superconductors materials ,some o

these have exotic properties which are not understoodthese have exotic properties which are not understood

or example, organic conductorsor example, organic conductors


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&roperties o super fuids:&roperties o super fuids:

'(resistance becomes zero'(resistance becomes zerothen the resistivity becomes zero then thethen the resistivity becomes zero then theconductivity becomes in)niteconductivity becomes in)nite

*(persistant current*(persistant currenti a current is set up in a superconductor iti a current is set up in a superconductor it

will fow orever without doing any voltwill fow orever without doing any volt

we might say it is an isolated systemwe might say it is an isolated system


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33((&erect diamagnetism&erect diamagnetism

super fuids expel a weak magnetic )eldsuper fuids expel a weak magnetic )eld+(the viscosity is zero+(the viscosity is zeroso super fuid is ideal fuidso super fuid is ideal fuid

)nally , scientists are searching in super)nally , scientists are searching in super

fuids until now in order to )nd materialfuids until now in order to )nd material

whose critical temperature is the roomwhose critical temperature is the roomtemperature $ t will be something amazingtemperature $ t will be something amazing

think they will do it think they will do it%hmed -ohamed Sabry %hmed -ohamed Sabry

super fluids

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