Importance of First Law of Thermodynamics (5 Best)

There are many reasons which makes the first law of thermodynamics very important.

Let’s discuss the importance of First law of thermodynamics.

#1 First law of thermodynamics is very important as it gives us the concept of energy conservation.

Explanation: 

First law of thermodynamics says that “Energy can neither be created nor destroyed, but it can be transformed from one form to another.”

Let’s take the example of a laptop or mobile phone to which you are looking at right now. 

The laptop or a mobile phone runs on a battery. 

Thus electrical energy of a battery is converted into light energy and heat energy of your device. (Display is the light energy and heating of laptop or mobile phone is the heat energy).

Similarly, the electric fan operates on the electric power supply.

Importance of First Law of Thermodynamics

Here, the electrical energy is converted into mechanical energy of the rotating fan.

In short, the energy is converted from one form to another. 

In this way, the first law of thermodynamics is important to understand the concept of energy conservation.

#2 First law of thermodynamics also shows the presence of internal energy in any substance.

Explanation:

All the bodies have atoms and molecules.

These atoms and molecules perform various types of motion like rotational motion, vibrational motion, translational motion, etc…

rotational motion, vibrational motion, translational motion

Due to these motions they possess some energy which is known as internal energy. 

The first law of thermodynamics shows the presence of internal energy in any substance.

#3 Using the mathematical form of the first law of thermodynamics (∆E = Q – W), we can find the heat, work and change in total energy/internal energy of any substance.

Explanation: 

In terms of heat, internal energy and work, the statement of first law of thermodynamics is given as;

“The net change in total energy of a system (∆E) is equal to the heat added to the system (Q) minus work done by the system (W).”

first law of thermodynamics equation

We can find the unknown values from this mathematical equation of the first law of thermodynamics.

#4 First law of thermodynamics is very important for understanding the basic concept and working of any devices in which one energy is converted into another.

Explanation: 

Just ask yourself, how does the electric heater heat up? 

electrical energy to heat energy

By using electrical energy.

How does the engine produce power?

heat energy to mechanical energy

By using the heat energy of the fuel. Right?

The above examples are the examples of the first law of thermodynamics which shows that one energy is converted into another.

Hence, first law of thermodynamics plays a vital role in understanding the conservation of energy.

#5 It is very important to keep in mind that the 1st law of thermodynamics is applicable everywhere and to all the objects (starting from small atom to huge planets, stars, etc)

Explanation:

Yes, even planets and stars obey the first law of thermodynamics.

Do you know why is sun so hot? And why does the sun give light?

The sun is hot because there is a continuous nuclear fusion occurring on the sun. Due to this nuclear fusion, the sun produces heat and light energy. 

Here also the energy is transferred from one form to another (chemical energy of hydrogen gas into heat and light energy of the sun).

Thus the law of conservation of energy is seen on the sun also.

I hope you have understood the importance of first law of thermodynamics.

For more detailed information on First law of thermodynamics, check the ultimate guide on First law of thermodynamics.

(This guide has all the important knowledge about First law of thermodynamics along with real life examples and lots more. You will love this guide for sure.)

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