 Hello friends, myself Sanjay Murt, Mechanical Engineering Department of Walchain Institute of Technology, Solaapur. Today, I am going to explain the thermodynamic part 3. Up till now, you have to know the part 1, part 2, and now part 3. All these are related to the thermodynamics introductions. That is the basic concepts, basic definitions of the thermodynamics. The learning outcome of this video is student will able to know thermodynamic processes, thermodynamic cycles, thermodynamic equilibrium and the statement of zeroth law of thermodynamics. Now, friends, when you go for a thermodynamic process and thermodynamic cycle, here in the graph 1 that is the pressure versus volume graph is to be there and it is to be given that it is one cycle that is here at the arrow it is a state 1. It moves from state 2 here through a path A or from A here state 1 is to be there. It moves to the state 2 through a path A 1, A 2 that is called as a process. And again it regained to its original character and completes one cycle, one loop is to be there. So, A B, 1 A B and 2 and 2 B 1, so 1 A 2 and 2 B 1 it is called as a one cycle. And here a process is given, here are two processes are there, one A 2 is one process and 2 B 1 is another process. In the second graph here it is given that 1 A 2 from here from initial point to the ending point that is one process. What is the process? Before going to the process in thermodynamics you know the state. What is the state? State means in the previous video I am explaining regarding the intensive property and extensive property and equilibrium conditions I am explaining. So, here the arrow at the starting point that is a state 1. In the state 1 it is an equilibrium condition. In the state 1 you know the it is pressure, volume, temperature, internal energy, enthalpy and from that one equilibrium condition some transaction is going on, heat is added or heat is rejected what you call work is added or work is detected. So, if this transaction is to be going on then it moves from initial stage to this final stage that is a two point that is a final stage, initial stage to the final stage. And it when it moves from initial stage to the final stage through a path A that is called as a one process. So, that process is from here to this here that is starting point to the end point that is called as a one process that is called as a thermodynamic process. That thermodynamic processes are two parameters minimum in the last lecture I am explaining here and the two parameters you can know it that transaction is going on. The pressure, volume, temperature is to be there minimum two characters by parameters you know it a pressure p v 1 is there, volume v 1 is there, temperature t 1 is there it moves from one equilibrium condition to the second equilibrium condition through a path A and at the end of this process there that values are p 2, v 2 and t 2 here. And initial is p 1, v 1, t 1 when it moves from state 1 to the state 2 through a process A through a path A that is called as a one process. When this process is carrying on you know the different process thermodynamic process are there constant pressure process, constant volume process and constant temperature process are to be there. So, one of the parameters is constant and other two are variable one. When you go for a p 1, v 1, t 1 one of the parameters is to be constant and it moves through a path A that is called as a path. Which path it will be followed if constant pressure process is to be there, constant volume process to be there, constant temperature process to be there. But one of the parameters is constant and other two are variable and it moves from one starting point to the end point through a path A and what you call through a path A and which path it will be followed that is to be very important. So, that is why some are intensive properties and some are extensive properties are there they are related to the end results and some are related which path it will be followed that is to be important. Now again from the here this is now a starting point means here it is a starting point and it comes to it followed a path B and again regain its original character where this original character initially it is a p 1, v 1, t 1 and some transaction is going on heat is added or heat is detected work is added or work is detected. Then it moves from initial point to the final point from one equilibrium condition to the another equilibrium condition from one state to the another state through a path A some values are to change initial values are p 1, v 1, t 1 final values are p 2, v 2 and t 2. Now here and again it moves another path some again transaction is going on heat is added or heat is detected work is added or work is detected and due to which it followed a path B and regain its original character and it completes one loop. So, cycle sorry process 1, A 2 and 2, B 1 when it completes one cycle that is called as a thermodynamic process it regain its original character means whatever the transaction is going on the first path heat added, heat rejected work added, work rejected and it comes to final condition equilibrium condition and again some transaction is going on through a path B heat added or heat rejected and again it regain its original character and it completes one loop that is called as a thermodynamic process and it is called as a thermodynamic cycle. So, in the previous when you go for a thermodynamic cycle from initial state to the final stage here it moves from a number of equilibrium condition means when it moves from A to B or B to A when A one equilibrium condition to the economic condition from state 1 to the state B state A to the state B it moves from some minute equilibrium conditions are there means here directly go to A to B some changes are going on and again come to equilibrium condition that is A 1 here it is A 2 here it is A 3 when we check the values from A 1 to the A 2 this A 1 to the A 2 some equilibrium changes are to be there and that changes are to be very minute and that is called as a quasi form very minute very negligible one, but some changes have to be going on. So, now A 2 to the A 3, A 3 to the A 4 when it to compare A 4 to the A 3 that changes are very minute when it to compare A 4 to the A that is to be large one that is a measurable one, but A 4 to the A 3 that values to be very negligible one, but some changes are to be there that is called as a quasi. So, it moves from number of quasi points are there number of equilibrium conditions are to be there when it moves from A to B that is called as a quasi static process means when it moves from one state to another number of quasi points are there number of equilibrium conditions are there and finally it comes to here means from P 1 to the P 2 there are what you call a number of quasi points are to be here that is a quasi static process. Now, you go for thermodynamic equilibrium thermodynamic equilibrium are that is that is in a stable condition that is called as a thermodynamic equilibrium that thermodynamic the word is thermal means heat related equilibrium conditions are there what are the equilibrium conditions are to be there there are thermal equilibrium conditions are there mechanical conditions are there chemical equilibrium conditions are there in thermal equilibrium conditions is there is no transaction of heat from system to the surrounding or state 1 to the state 2 or that quasi points are to be there There is no changes of the heat, they are in a stable condition related to the heat. We need to go for a mechanical equilibrium conditions, there is no unbalanced forces acting on that, that is in a equilibrium condition from state 1 to the state 2, whatever the process going on that is in a mechanical equilibrium conditions. And the chemical equation there is no transaction, there is no configuration in that system. So, these are the three equilibrium condition you can study it in the thermodynamics. Thermal equilibrium conditions, mechanical equilibrium conditions and chemical equilibrium conditions are there that is related to the thermodynamic. Suppose you go for is here hot body and cold body, some transaction is to be going on that is related to the thermal, that is related to the mechanical, that is related to chemical that you have to mention it, you have to study it when it moves from state 1 to the state 2, when it moves from or it completes one process, you know it completes one cycle at that time you can shake it, you can mention it which equilibrium conditions in which process. We need to go for here, we need to go for this loop 1 that is two processor 1, A 2 and 2, B 1, two process each time you can mention which equilibrium are to be there, thermal equilibrium is there, mechanical equilibrium is there or chemical equilibrium are to be there. So, that is the definition of thermal equilibrium. Next one we have to go for the statement of zeroth law of thermodynamics. This zeroth law of thermodynamics related to that there is a equality of temperature, temperature moves from this hot body to the cold bodies are to be there. So, we have to think over that, what are the different equilibrium conditions you can know it, in regular you can used it, think over that, just give some example for this equilibrium. Thermal equilibrium condition what you call refrigerated area is to be there, in that refrigerated area temperature remains constant, thermal equilibrium is to be there. One example mechanical equilibrium, any body is to be at its time still condition, stable condition is to be there, there is no transactions, the mechanical equilibrium that is in a stopped condition, working condition is what you call initial condition is to be there, stopped the condition that is the mechanical equilibrium is there. So, these are the examples of this thermodynamic equilibrium conditions are to be there. Thank you.