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# NCERT Solutions Class 11 Physics Chapter 11 Thermodynamics - PDF Download

Class 11

NCERT Solutions for Class 11 Physics Chapter 11 Thermodynamics will give you the self-confidence to face the exam without fear. In this chapter, you will study the laws which govern thermal energy. The process where work is converted into heat and vice versa is described in brief in this chapter11. To help students understand the basic concepts of this chapter, we at our website eSaral, have designed the chapter-wise NCERT Solutions according to the updated board Syllabus 2023-24 in PDF format, which can be accessed at any time and at any place.

Thermodynamics chapter 11  is all the concepts of temperature and heat and their conversion to other forms of energy. This chapter also has numericals, and their regular practice is important to perform well in the exam. The solutions contain key concepts highlighted, formulas and definitions in simple language to help students revise the chapter a few days before the exam. You can get the free PDF of NCERT Solutions for Class 11 Physics from the link given below.

Thermodynamics is one of the most scoring topics in Physics NCERT Solutions for Class 11. You must study this Chapter in-depth to excel in the exam. Following are some key points of Thermodynamics are given below.

• Equilibrium in thermodynamics refers to the situation when macroscopic variables describe the thermodynamic state of a system which does not depend on time. Equilibrium of a system in mechanics means the net external force and torque on the system are alway zero. The temperature of a body is correlated to its average internal energy, not to the kinetic energy of motion of its center of mass.

• Heat capacity, in general, depends on the process of the system that goes through when the heat is supplied on the system.

• In a state of thermodynamic equilibrium, the microscopic constituents of a system are not in equilibrium state.

• In isothermal processes, heat is absorbed or given out by the system even though, at every stage, the gas has the same temperature as that of the surrounding reservoir. This is mainly because of the infinitesimal difference in temperature between the system and the reservoir.

## Subtopics of Class 11 Physics Chapter 11 Thermodynamics

• Introduction

• Thermal equilibrium

• Zeroth law of Thermodynamics

• Heat, internal energy and work

• First law of thermodynamics

• Specific heat capacity

• Thermodynamic state variables and the equation of state

• Thermodynamic processes

• Second Law Of Thermodynamics

• Carnot Engine

### Introduction

Thermodynamics is the branch of physics which deals with the concepts of heat and temperature and the inter-conversion of heat and other forms of energy. Thermodynamics is a macroscopic science that deals with bulk systems and does not go into the molecular constitution of matter. Thermodynamics concepts and laws were formulated in the nineteenth century before the molecular picture of matter was firmly established. Its description involves relatively few macroscopic variables of the system, which are suggested by common sense and can be usually measured directly.

### Thermal Equilibrium

In this topic we will learn about thermal equilibrium and we understand this topic with the example. Thermal equilibrium is the physical state of two bodies or objects when they are connected by a permeable path, don't undergo any heat transfer and both the bodies have the same temperature.

### Zeroth Law of Thermodynamics

In this topic we will discuss the Zeroth law of thermodynamics with examples and figures. When a body, 'A', is in thermal equilibrium with another body, 'b', and it is also separately in thermal equilibrium with a body ', C', then body, 'B' and 'C', will also be in thermal equilibrium with each other so, this statement defines the zeroth law of thermodynamics.

### Heat, Internal Energy And Work

Heat: The Zeroth Law of Thermodynamics teaches us the concept of temperature that agrees with our commonsense notion. Temperature is a notation of the ‘hotness’ of a body. It determines the direction of flow of heat when two bodies or objects are placed in thermal contact. Heat flows from the body at a higher temperature to lower temperature. The flow stops when the temperatures come in equilibrium; the two bodies are then in thermal equilibrium.

Internal Energy: The concept of internal energy of a system is very easy to understand. As we know that every bulk system consists of a large number of molecules. Internal energy is simply known as the sum of the kinetic energies and potential energies of these molecules.

## First Law of Thermodynamics

The energy (∆Q) supplied to the system goes in partly to increase the internal energy of the system (∆U) and the rest in work on the environment (∆W). Following equation is known as the First Law of Thermodynamics.

It is simply based on the general law of conservation of energy applied to any system in which the energy transfer from or to the surroundings is taken into account.

The internal energy ‘U’ of a system can change through two modes of energy transfer : heat and work. Let ∆Q = Heat supplied to the system by the surroundings

∆W = Work done by the system on the surroundings

∆U = Change in internal energy of the system The general principle of conservation of energy then implies that ∆Q = ∆U + ∆W

### Specific Heat Capacity

Specific heat is known as the quantity of heat required to raise the temperature of one gram of a substance by one Celsius degree. The units of specific heat are usually in calories or joules per gram per Celsius degree.

### Thermodynamic State Variables And The Equation of State

These parameters are defined as state variables, for instance temperature (T), pressure (P), volume (V ), entropy (S), enthalpy (H), internal energy (Q), mass (m), density (ρ). Equation of state is a relation between temperature, pressure, moles, and volume that helps determine us to the properties of a system.

### Thermodynamic Processes

A Thermodynamic process is a process in which the thermodynamic state of a system is changed. A change in a system is defined by a passage from a start to a final state of thermodynamic equilibrium.

## Second Law Of Thermodynamics

The second law of thermodynamics says that any spontaneously occurring process will always lead to an escalation in the entropy (S) of the universe. In simple words, the law explains that an isolated system's entropy will never decrease over the period of time.

## Benefits of NCERT Solution for Class 11 Physics Chapter 13 PDF

Most students study reference books alongside their NCERT books as an effort to gain further insight into the subjects. Referring to our Class 11 Physics NCERT solutions chapter 13 will help you in numerous ways, some of which are:

• Simplify Learning

NCERT Solution for Class 11 Physics Chapter 11 was curated with the prime objective of helping you in your studies.

NCERT solutions for Class 11 physics chapter 11 PDF is created by a team of expert physics teachers. Our expert subject teachers are the masters in their own field - teachers, lecturers or PhD holders in the subject.

• Problem-Solving Approach

A problem-solving approach to studying by NCERT solutions for Class 11 Physics Chapter 11 PDF is designed to maximise your understanding of this chapter 11.

Chapter 11 Class 11 Physics NCERT solutions answer every question and clarify all your doubts for a better learning experience. You can clear your doubts by our solutions, making learning a fun activity.

• Free Resource

NCERT solutions Class 11 is available in a PDF format for your convenience on our website.

Question 1:  What are the Laws of Thermodynamics?

Answer: There are three laws of Thermodynamics which are the flow of heat and energy.

First Law - The energy (∆Q) supplied to the system goes in partly to increase the internal energy of the system (∆U) and the rest in work on the environment (∆W). Following equation is known as the First Law of Thermodynamics.

It is simply based on the general law of conservation of energy applied to any system in which the energy transfer from or to the surroundings is taken into account.

The internal energy ‘U’ of a system can change through two modes of energy transfer : heat and work. Let ∆Q = Heat supplied to the system by the surroundings

∆W = Work done by the system on the surroundings

∆U = Change in internal energy of the system The general principle of conservation of energy then implies that ∆Q = ∆U + ∆W

Second Law - The second law of thermodynamics says that any spontaneously occurring process will always lead to an escalation in the entropy (S) of the universe. In simple words, the law explains that an isolated system's entropy will never decrease over the period of time.

Third Law - This law says that entropy of a system approaches a constant value with the temperature reaching zero.

Question 2: What are the topics in chapter 10 Thermodynamics?

Answer: Subtopics of Class 11 Physics Chapter 10 Thermodynamics

• Introduction

• Thermal equilibrium

• Zeroth law of Thermodynamics

• Heat, internal energy and work

• First law of thermodynamics

• Specific heat capacity

• Thermodynamic state variables and the equation of state

• Thermodynamic processes

• Heat engines

• Refrigerators and heat pumps

• The second law of thermodynamics

• Reversible and irreversible processes

• Carnot Engine