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DIFFRENCE BETWEEN HEAT AND WORK !

HEAT and WORK plays vital role in thermodynamics.

Its very common misunderstanding between peoples that they are ENERGY but they are not energy they are medium by which we transfer energy   . 

although they don't seem to be identical because heat  is thermal property and work is mechanical property but they are same  , at microscopic level they both are same phenomenon . 

 

HEAT

 

They are just moving of molecules , having difference is only , heat is moving of molecules disorderly in any direction OR in other words heat is microscopic collision of molecules .

WORK

 

Work is moving of molecules  in only single direction OR in other words work is macroscopic push and pulls ( given by product of force and displacement ) . both shares same SI unit as JOULE .

We termed work as high grade energy and heat as low grade energy 

Because in reversible or irreversible process we can convert work 100 % in heat we can convert heat into work 100 % in irreversible process but we can't convert heat with 100% efficiency in work by performing reversible process .

like nature don't want to welcome reversible process  in clique with heat , when we convert heat in work   while performing  reversible process some heat always losses and this fact became to call work as high grade and heat as low grade energy .

Positive and negative values of WORK (W)and HEAT(Q)
 

W > 0 when a gas is compressed. Energy is transferred into system.

W < 0 when a gas expands. Energy is transferred out of system.

 
Q > 0 when the environment is at a higher temperature than the system. Energy is transferred into system. 


Q < 0 when the system is at a higher temperature than the environment. Energy is transferred out of system.

 CONVERSION OF HEAT & WORK 

 

Conversion of heat in to work happens at some specific rate you can call it conversion rate of this two thermodynamics coordinate's -

4.18J=1 CALORIE OF HEAT 

and its your WILL to use any method to change work in heat or vice-versa ,but to produce 1 calorie of heat you always have to do 4.18 J of work also known as mechanical equivalent of heat or joule's equivalent . 




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