First and Zeroth Law of Thermodynamics

 First law Of Thermodynamics;

• To understand thermodynamics well and to make any calculations in thermodynamics, it is extremely important that we have its basic rules. These are some of the basic laws of thermodynamics.The first law of thermodynamics in  will try to understand about this very useful rule through medium.
• Heat was not considered a form of energy when thermodynamics was developing. But after some time it was proved that heat is also a form of energy, after that an attempt to find a relationship between heat and work started.
• Heat and work are two different forms of the same entity, and that entity is called energy. This means that if heat is supplied to a system, it can come out as work, or as work is done on a system, it can come out as heat.
• While the relationship between heat and work came out, a new term introduced the whole world, which was called internal energy. The first law of thermodynamics shows the relation between heat, work and internal energy.

First law of thermodynamics statement

• Thermodynamics is the first law of the law of conservation of energy. It states that "Energy can neither be created nor destroyed. Its disposition can be modified."
• In this way, this rule only explains energy conservation. The law of conservation of energy also says that the energy of this entire universe is conserved. It cannot be erased.

First law of thermodynamics for a cycle

• When a system follows a cycle, it will be at the same point at the start and end of the system. The reason for this is that a system running a cyclic process performs a certain type of process over and over again.
• Take an example to understand the cyclic process in easy language. A person leaves his house for office in the morning, and returns to his home in the evening. In this way, it is called a cyclic process, because the person may have come in the midst of many things, but his former and last place or position was the same.
• Thus if one is following a cyclic process then speaking of the system there is "the net workflow done by the system will be equal to the total heat supplied to the system." In this situation there will be no change in the internal energy of the system. This rule applies for closed systems.
• If the system is getting heat through several different mediums throughout the cycle, or the system is going to sort the heat around. Also, if the system is doing many types of work, then in this case the total heat supplied to the system will be equal to the total work done by the system.

        It can be written in this way.

                           (Integration of work) = (integration of heat)

• Integration refers to the addition of all small amounts of heat and work.
• This rule applies when the system is operating in a cycle. We know that the beginning and ending point of a cycle is the same. In this case, the internal energy of the system will not matter, because the internal energy is a point function.

First law of thermodynamics for a process:

•  Any cycle consists of 2 or more paths. We can also apply this rule on different paths of the cycle. To understand this easily, we assume that there is a circle, which consists of two paths. We can call them process.
•  Let's talk about a process. In this, if we supply Q jule heat, and the system acts as a W jule during this process. So this equation will make something like this.

 

First law of thermodynamics

                                                                   Q = W + ∆U

 

• Here, U represents the change in the internal energy of the system. It is important to know here that the first law of thermodynamics never indicates anything about the internal energy of a system, but it does organize the variable in internal energy. 

         In this way there is no internal change during the cycle. Hence

     

                          △U = 0

 

             And becomes Q = W.

Zeroth Law Of Thermodynamics:

• Friends, when we talk about Thermodynamic, then Zeroth Law Of Thermodynamics is an important rule. What is Zeroth Law Of Thermodynamics? Before knowing what is the importance of Zeroth Law of Thermodynamics in Thermodynamics, he knows about the history of this rule.
• You will know that Thermodynamics mainly operates on 4 rules. Although there are many other rules, but the entire Thermal Science has been kept by these 4 rules. These are the four rules.

1. Zeroth law of thermodynamics
2. First law of thermodynamics
3. Second law of thermodynamics
4. Third law of thermodynamics

Zeroth Law of Thermodynamics was first told by R H Fowler. It is important to know here that the interpretation of First Law and Second Law was done before Zeroth Law. Then the question arises that why Zeroth Law was not called Third Law?

The reason behind this is that the principle which was explained in Zeroth Law of Thermodynamics was very basic. This was considered a fundamental principle of Thermodynamics, hence this rule was named as Zeroth Law of Thermodynamics.

What does Zeroth Law Of Thermodynamics explain?

Zeroth Law Of Thermodynamics.

• Explains the direction of flow of heat.To explain how hot an object is, how cold it is, we need a numerical value, this numerical value is called temperature. 
• When we feel an object by touching it, then on the basis of the degree of hotness of that object, we say that the object is hot, or cold. But only on the basis of experience, it is difficult to tell the temperature of that object in a certain number.
•  Along with this, the experience of our skin also sometimes deceives us. For example, if you touch two objects, the first is a metal object. Another wooden object. Now of course you will feel a bit colder than a metal object. 
• There is a reason behind this. But it can also happen that both the objects have the same temperature, but your experience has made you feel different temperature.

Let's see another example, 

• when we keep any hot liquid like tea in an open environment, it cools down, but if we keep ice or cold drinks in an open environment, then they get hot. Why does this happen? Such phenomena make us think that what is the law of flow of temperature? An object is cold coming in contact with the atmosphere, so at the same time, why does an object get hot in contact with the atmosphere?

• Zeroth Law of Thermodynamics explains this law of science. This rule states that the flow of heat is not always the same. It depends on the temperature of the object and the atmosphere, how the heat will flow.

Zeroth Law Of Thermodynamics.

• If any two bodies are in Separately Thermal Equilibrium from a Third Body, then both these bodies will also be in Thermal Equilibrium from each other.

Zeroth Law Of Thermodynamics

• This rule became the main basis of temperature measurement. Today we use Thermometer etc. to measure temperature. If we remove the third body from this rule, and use a thermometer in its place, then this rule can also be interpreted in this way.
• If the temperature of any two bodies is the same in a thermometer, then that body will be in thermal equilibrium for each other, even if those two bodies are not in contact with each other.

• Now a word is coming over here, Thermal Equilibrium. When the temperature of any two or more objects becomes equal, there is no transfer of heat in them, this state is called the State of Thermal Equilibrium. The transfer of heat is always from the hot object to the cold object, and it continues until the temperature of the two objects is the same. This is the state of Thermal Equilibrium.