Thermal Properties of Matter Class 11th Notes - Free NCERT Class 11 Physics Chapter 11 Notes - Download PDF

The NCERT chapter on Thermal Properties of Matter is the chapter primarily focuses on thermal properties of matter, in which we will investigate the properties of various substances as a result of heat / heat transfer. The NCERT Class 11 Physics chapter 11 that is Thermal Properties of Matter Class 11 Notes provides a high-level overview of the chapter. The key topics covered in Thermal Properties of Matter Class 11 notes are temperature and heat, measurement of temperature, ideal-gas equation and absolute temperature, absolute zero, change of state, and many others.

The chapter's basic equations are also addressed in Class 11 Physics chapter 11 notes. The Thermal Properties of Matters Class 11 notes pdf download covers all of these topics. The essential derivations are not covered in the CBSE Class 11 Physics chapter 11 notes.

Also, students can refer,

• NCERT Solutions for Class 11 Physics Chapter 11 Thermal Properties of Matter
• NCERT Exemplar for Class 11 Physics Solutions Chapter 11 Thermal Properties of Matter

NCERT Class 11 Physics Chapter 11 Notes

Heat and Temperature

Temperature is the measurement of a body's degree of hotness or coolness.
Example:-

A cup of hot soup or an ice cream scoop

Heat is a kind of energy that is exchanged via temperature difference between two (or more) systems or between a system and its surroundings.
For example, a cup of hot coffee might be regarded an object or system, whereas everything else is the environment.

As a result of the temperature difference, heat will move from one thing to another.

The S.I Unit of Heat is joule.

Temperature Measurement

A thermometer is used to determine the temperature.

In, liquid-in-glass thermometers, mercury and alcohol are regularly used liquids.

The following graph depicts the relationship between temperature in Celsius and Fahrenheit graphically:-

Where t_f means Fahrenheit temperature

t_c means Celsius temperature

Absolute Temperature and the Ideal-gas Equation

A thermometer that employs any gas, on the other hand, will produce the same readings regardless of the gas used since all gases expand at the same rate at low temperatures.

The following variables are used to characterise the behaviour of gas:

• Quantity(mass)

• Pressure

• Volume

• Temperature

Gases with a low density obey the following rules: -

1.Boyle’s Law– In this law product of PV = constant(when temperature T is constant)

2.Charles’ Law- In this law ratio of V/T = constant (when pressure P is constant)

When both of the preceding principles are combined, the equation becomes PV = RT, where R stands for universal gas constant.

Absolute Zero
The minimal absolute temperature of an ideal gas is defined as Absolute Zero.
We get a straight line if we plot pressure versus temperature and then extend the line backwards to the x-axis, as seen in the graph below.

The lowest temperature measured (experimentally) was -273.15 °C, which is known as absolute zero.

The relationship between temperature in kelvin and temperature in Celsius is provided by

Thermal Expansion

Thermal expansion is the phenomena of a body's dimensions expanding as its temperature rises.

Thermal Expansion Types

Expansion in length is known as linear expansion.

Expansion in area is known as area expansion.

Volume Expansion: This is a term that refers to the increase in volume of anything.

Linear Expansion

The term "linear expansion" refers to the length of anything expanding as the temperature rises.

The term "linear expansion" refers to a fractional change in length, or how the length changes in relation to the original length.

ΔL is the length change, L is the initial length, ΔT is the temperature change, and α_L is the linear coefficient of thermal expansion.

Area Expansion

The term "area expansion" refers to the expansion of an area as a result of an increase in temperature.

There is an increase in both length and width when an area is expanded.

Where α_a = coefficient of area expansion.

Volume Expansion

It is defined as the expansion of volume as a result of an increase in temperature.

This indicates that a substance's length, width, and height have increased.

Where α_v = coefficient of volume expansion.

Anomalous Behavior of Water

At 4 °C, water has the highest density.

When the temperature drops below 4 °C, the water expands, and the density falls.

Because of this feature, water in lakes and ponds only freezes at the top layer and not at the bottom, but if the water freezes at the bottom as well, animal and plant life would be unable to survive.

Heat Capacity

A quantity termed the heat capacity of a substance characterises the change in temperature of a substance when a particular amount of heat is absorbed or rejected by that substance.

Mathematically,

Where ΔQ is amount of heat supplied to the substance and ΔT change in its temperature.

Specific heat capacity:

Specific heat is the amount of heat received or rejected per unit mass by a substance to change its temperature by one degree.

Molar specific heat capacity: -

The heat capacity per mole is the amount of heat (in moles) absorbed or rejected by a substance to change its temperature by one unit.

The molar specific heat capacity (C_p) is defined as follows:

The equivalent molar specific heat capacity at constant pressure is called molar specific heat capacity at constant pressure if the gas is retained at constant pressure during the heat transfer (C_p).

Molar specific heat capacity (C_v):-

The equivalent molar specific heat capacity at constant volume is called molar specific heat capacity at constant volume if the volume of the gas is maintained during the heat transfer (Cv).

Calorimetry

Calorimetry consists of two words:

Calorie is a word that meaning "heat" and "metry" is a word that means "measuring."

As a result, the term "calorimetry" refers to the measuring of heat.

Calorimetry is the transfer of heat from a hotter body to a cooler body while avoiding heat loss to the atmosphere.

Calorimetry is based on the idea that the heat lost by one body is equal to the heat absorbed by another. Calorimeter is the name of the device that measures calorimetry.

Change of State

Change of state refers to the transition from a solid to a liquid or from a gas to a liquid or solid.

Melting is the transformation of a solid (ice) into a liquid (water).

Fusion is the transformation of a liquid (water) into a solid (ice).

Thermal Equilibrium: During this state, there is no heat loss or gain.
The melting point of a substance is the temperature at which its solid and liquid states are in thermal equilibrium with one another.

normal melting point:- The normal melting point of a substance is its melting point under standard atmospheric pressure.

Regelation:- The phenomena of regelation is defined as the process of lowering the freezing point of water by applying pressure.

Vaporization :-Vaporization is the process of changing from a liquid to a gas.

The transition from a liquid to a vapour (or gas) is known as vaporisation.

Sublimation :-Sublimation is the transformation of a solid into a gas.

Both the solid and vapour states of a substance coexist in thermal equilibrium throughout the sublimation (solid converts to vapour without going through liquid state) process.

Significance of NCERT Class 11 Physics Chapter 11 Notes

Class 11 notes on Thermal Properties of Matter will be helpful in revisiting the chapter and getting a sense of the main themes discussed.

By covering the fundamental topics of the CBSE Physics Syllabus in Class 11, these NCERT Class 11 Physics chapter 11 notes can also be used to study for competitive exams such as VITEEE, BITSAT, JEE Main, NEET, and others.

When you are not connected to the internet, you can use the Class 11 Physics chapter 11 notes pdf download to study.

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