Heat Vs Work

The transfer of energy between the system and the surrounding takes place in two ways, namely heat and work. In general, both heat and work differ in behavior. But in thermodynamics, both of these are the ways of energy transfer between the system and the surrounding. The first one, heat is the transfer of thermal energy between system and surrounding (or between two systems) and the second one, work is the transfer of mechanical energy between system and surrounding (or between two systems). 
Heat energy will be transferred from a higher temperature object to a lower temperature object.

Comparation between heat and work
  1. Heat is a form of energy while work is not a form of energy.
  2. Heat can be converted into work completely while the work can't be completely converted into heat. This means that the efficiency of the equipment converting heat into work can be 100%. But the efficiency of a device that converts work into heat can never be 100%.
  3. Heat is a low grade energy while the work is a high grade energy.
  4. Heat transfer between the system and surrounding when the driving force between them is temperature difference while the work transfer between the system and surrounding when the driving force between them is something othar than temperature difference.
  5. Heat stimulates the random motion of the particles whereas work stimulates the organized motion of the particles.
  6. When there is no transfer of heat between the system and the surroundings, then we can say that the system and the surroundings are in thermal equilibrium with each other. And when there is no transfer of work between the system and the surroundings, then we can say that the system and the surroundings are in mechanical equilibrium with each other.
  7. Heat and work are the forms of energy interaction or dynamic forms of energy. Heat➝ Microscopic motion While Work➝ Macroscopic motions
Sign convention
Here, we will see the sign conventions used for heat and work transfer in thermodynamics.
➝ Heat added to the system = +ve
     Work done on the system = +ve
In this, system's energy increases
because energy is transferred from surrounding to system.

➝ Heat librated from the system = -ve
     Work done by the system = -ve
              ( ஃ W<0 and Q<0 )
In this, system's energy decreases because energy is transferred from the system to Surrounding.

What Is The Difference Between Heat And Energy??
Heat is a transfer of energy from a body of high temperature to a body of lower temperature.
Energy is the ability of a body to do work.


Hope you have found this article helpful!!
Feel free to comment if you have any queries!!!

Comments

Post a Comment

Most Viewed Posts

Zeroth Law Of Thermodynamic: The Thermal Equilibrium Law

Image
In thermodynamics, we will see two types of walls. One is the Diathermic wall and the other is the adiabatic wall. Let us now go through them one by one.  • So the first is the Diathermic wall- " A Diathermic wall is a wall that allows the easy exchange of heat between two bodies (or between two systems or between system and surrounding) but does not allow the exchange of mass between them ". This means that it is a good conductor of heat. It is sometimes called as metallic wall because it is made of metal. • While the other is the adiabatic wall- " An Adiabatic wall is that wall which neither allows exchange of heat nor mass between two systems (or between system and surrounding) ". Since there is no exchange of heat and mass between the system and its surroundings, the system remains insulated from its surroundings. ➛ That's why whenever we separate the two systems by an adiabatic wall, then there is no concept of equilibrium between them. But whenever we sep...
Read more

Characteristics Of Entropy

Image
Entropy is an intrinsic property of a substance and is not affected by the external position of a system or its motion relative to other systems. It is a measure of the randomness of the system. Thus, the higher the randomness of the system, the higher the entropy of the system and the lower the randomness of the system, the lower the entropy of that system. Entropy   " Entropy is defined as a measure of the system's thermal energy that is incapable of doing work ". It is a state function.  For Example Heat is a form of energy that is incapable of doing work. Therefore, the more heat added to the system (or tranfer from the system), the higher (or the lower) will be its entropy.  The formula for change in entropy is given by the equation;                      ➩ ∆S = ∆Q/T For a reversible process, the change in entropy is given as; The Total Change In Entropy Entropy change is zero at equilibrium condition or whenev...
Read more

Reversed Carnot Cycle

Image
We have already discussed the concept of “ Carnot Cycle ”   & “ Its Efficiency ” and we have also seen the concept of “ Carnot Theorem And Its Explanation ” in our previous post. As we have already discussed that the Carnot Cycle is a reversible cycle and every process in the Carnot cycle is a reversible process. Therefore, every process of the Carnot cycle can be reversed. And the cycle can be operated in the opposite direction as well. In this article, we're interested in learning more about the reversed Carnot cycle, also known as the reversed Carnot heat engine cycle. Reversed Carnot Heat Engine It is important to note that if a reversible process is reversed, all related energy types—such as heat energy or work energy—will have the same magnitude but the direction of their interaction with matter will be changed. Let us first look at the Reverse Carnot Heat Engine  cycle here; The reversed Carnot heat engine cycle is depicted in the following figure. According to the...
Read more