Thermal Properties of Matter - Definition, Formulas, Examples, FAQs

The thermal properties of matter are the essential characteristics that govern how substances respond to changes in temperature and energy transfer. In this article, we will explore the thermal expansion of solids, liquids, and gases, specific heat capacity, modes of heat transfer, thermal conductivity, and the laws related to blackbody radiation. By examining these properties, we can gain insights into the behaviour of materials under thermal conditions. This article provides a foundational understanding that is crucial for class 11 students. Students should check the Thermal Properties of Matter class 11 notes to download the pdf containing notes.

Thermal Properties Of Matter Class 11 Important Topics (NCERT Syllabus)

1. Heat, temperature, thermal expansion of solids

2. Thermal expansion of liquids, and gases

3. Anomalous expansion of water

4. Specific heat capacity

5. Calorimetry

6. Change of state - latent heat

7. Heat transfer-conduction, convection and radiation

8. Thermal conductivity

9. Qualitative ideas of Blackbody radiation

10. Wein's displacement Law, Stefan's law.

Thermal Properties Of Matter Class 11 Notes

1. Heat, Temperature And Thermal Expansion Of Solids

Temperature is defined as the degree of hotness or coldness of a body and its measurement is thermometry. Temperature is a fundamental quantity. It is a scalar with S.I. unit Kelvin. The temperature decides the direction of heat flow. Heat flows from a point of higher temperature to a point of lower temperature. The temperature of a body is a measure of the average translational KE of a molecule.

$(K \cdot E) \propto(T)_k$

Scales of temperature: The SI unit of temperature is kelvin, defined as (1/273.16)th part of the thermodynamics temperature of the triple point of water. Celsius scale or centigrade is also common.

Nowadays in new thermometry triple point of water 273.16 K is taken as the reference point. The triple point of water is 0.01 on the Celsius scale and 273.16 K on the Kelvin scale.

Conversion between different scales

$\frac{\mathrm{C}^{\circ}}{100}=\frac{\mathrm{F}-32^{\circ}}{180}=\frac{\mathrm{K}-273}{100}$

2. Anomalous Expansion Of Water

Generally, any material expands on heating and contracts on cooling. But in the case of water, it expands on heating if its temperature is greater than 4°C. In the range 0°C to 4°C, water contracts on heating and expands on cooling, i.e. $\gamma$ is negative. So water has this special property, which is not found in any existing natural material. This behaviour of water in the range from 0°C to 4°C is called anomalous expansion.

3. Specific Heat Capacity

• Specific Heat Capacity Notes

4. Calorimetry

• Calorimetry Notes

5. Change Of State - Latent Heat

• Change Of State- Latent Heat Notes

6. Heat Transfer - Conduction, Convection And Radiation

• Heat transfer- conduction, convection and radiation notes

7. Thermal Conductivity

• Thermal Conductivity Notes

8. Black Body Radiation

• Black body radiation notes

• Newton’s Law Of Cooling

Newton's law of cooling notes

9. Wein’s Displacement Law And Stefan’s Law

• Wein's displacement law notes

• Stefan's law

Other Important Topics

• Ideal gas law notes

Thermal Properties Of Matter Important Formulas

1. Heat Transfer

• Conduction

$Q=\frac{k \cdot A \cdot\left(T_1-T_2\right) \cdot t}{d}$

• Convection

$Q=h \cdot A \cdot\left(T_s-T_{\infty}\right) \cdot t$

• Radiation

$Q=\varepsilon \cdot \sigma \cdot A \cdot\left(T^4-T_{\text {sur }}^4\right) \cdot t$

2. Specific Heat Capacity

• Heat Transfer

$Q=m \cdot c \cdot \Delta T$

• Latent Heat

$Q=m \cdot L$

• Ideal Gas Law

$P V=n R T$

3. Thermal Expansion

• Linear Expansion

$\Delta L=\alpha \cdot L_0 \cdot \Delta T$

• Area Expansion

$\Delta A=2 \alpha \cdot A_0 \cdot \Delta T$

• Volume Expansion

$\Delta V=\beta \cdot V_0 \cdot \Delta T$

Thermal Properties Of Matter Applications

• Building Insulation

• Refrigeration and Air Conditioning

• Heat Exchangers

• Thermal Management in Electronics

• Cooking Appliances

• Phase Change Materials

• Medical Applications

• Astronomy and Space Exploration

NCERT Solutions Subject-wise link:

• NCERT solutions for class 12 Physics.

• NCERT solutions for class 12 Chemistry.

• NCERT solutions for class 12 Mathematics.

• NCERT solutions for class 12 Biology.

Importance Of Chapter Thermal Properties Of Matter

• Understanding Fundamental Concepts: Understanding topics like radiation, convection, and conduction is essential for fields like environmental science, and meteorology.

• Real-Life Applications: The concept of thermal properties of matter can be used for thermal therapy in medical applications, thermal control systems in spacecraft and thermal energy storage systems in phase change materials.

• Material Selection: Knowing the specific heat capacity and thermal properties of materials would help us in selecting materials for manufacturing or industrial purposes.

• Thermodynamics Foundation: This unit underlays the groundwork for advanced topics in thermodynamics.

• Energy Conservation: Understanding the thermal properties encourages awareness of energy conservation and sustainability.

• Problem-Solving Skills: Solving complex problems in this unit would help students to enhance problem-solving skills in advanced topics.

Summary

The unit on thermal properties of matter in Class 11 physics plays a crucial role in understanding how heat and temperature affect different materials. This principle has applications in everyday life. It covers essential concepts such as heat transfer mechanisms—conduction, convection, and radiation—along with specific heat capacity and thermal expansion. This concept has an interdisciplinary connection with fields like chemistry, environmental science, and engineering.