Graphical Comparison of Thermodynamic Processes - Testbook

Last Updated on Feb 05, 2025

IMPORTANT LINKS

Thermodynamics

Branches of Physics Murphys Law Weightlessness Braille Humidity The International System of Units Measurement of Speed Spherometer Micrometer Sonometer Difference Between Mass and Volume Unit of Mass Difference Between Density and Volume Density of Air Relation Between Pascal and Bar Impulse Units Relation Between Calorie and Joule Difference Between Kva and Kw Unit of Pressure Relation Between Pressure and Density

Thermodynamics is a fascinating field in physics that primarily focuses on the interaction of different energy forms, including heat. It's interesting to see how it describes the transformation of thermal energy into other energy forms and how this affects matter.

What is a Thermodynamic Process?
A thermodynamic process is essentially an energy transfer within or between systems. Properties such as pressure, temperature, and volume play a significant role in these processes. The current values of these properties define the thermodynamic state of the system. A simple example of a thermodynamic process could be the heating of water in a kettle. The kettle's system absorbs heat from its surroundings (the stove), leading to a rise in the water's temperature.

Various Types of Thermodynamic Processes
Isobaric Process: In this process, the pressure remains constant. Consider a balloon being inflated. The pressure inside the balloon remains constant as it expands, illustrating an isobaric process.
Isothermal Process: This process is characterized by a constant temperature. An example of this process would be a hot cup of coffee left in a room. Over time, the coffee cools down to match the room temperature, indicating an isothermal process.
Adiabatic Process: This process involves no heat transfer between the system and its surroundings. However, the system's temperature may change due to internal variations. A good example is an insulated flask containing a hot beverage. The flask's insulation prevents heat transfer, making it an adiabatic process.
Isochoric Process: This process is characterized by a constant volume. An example would be heating air in a sealed container. Since the container is sealed, the volume remains constant, making it an isochoric process.

Understanding the Polytropic Process
A polytropic process is a specific type of thermodynamic process that follows the equation PV^x = C, where P is Pressure, V is Volume, x is the Polytropic Index, and C is a Constant. The polytropic index can take any value between 0 and infinity, depending on the process.

Value of x (PV^x = C) Process

x = 0 Isobaric (dP = 0)

x = 1 Isothermal (dT = 0)

x = n Polytropic

x = γ Adiabatic (δQ = 0)

x = ∞ Isochoric (dV = 0)

Test Series

NCERT XI-XII Physics Foundation Pack Mock Test

323 TOTAL TESTS | 5 Free Tests

3 Live Test
163 Class XI Chapter Tests
157 Class XII Chapter Tests

Get Started

Visualizing Thermodynamic Processes: The Graphical Approach
Pressure-volume or PV diagrams are useful tools to visualize the changes in pressure with respect to volume in a thermodynamic process. They can also be used to determine a system's efficiency. The area under the curve of a PV diagram represents the work done by or on the system.
The PV diagram for expansion shows that for the same volume of expansion, the area under the isothermal curve is greater than that under the adiabatic curve. This implies that more work is done in the isothermal process than in the adiabatic process. Work done due to expansion is calculated as positive.
On the other hand, the compression curve shows that the area under the adiabatic curve is greater than that under the isothermal curve. In compression, the work done is calculated as negative. Thus, even in compression, more work is done in the isothermal process than in the adiabatic process.

Frequently Asked Questions

Define escape velocity.

The minimum speed required to project a body vertically upward from the earth’s surface so that it never returns to the earth’s surface is called escape speed or escape velocity.

Write the expression for escape velocity.

vₑ = √2GM/R =√2gR where R is the radius of the earth and g is the acceleration due to gravity.

What is the value of escape velocity on the surface of the earth?

The value is 11.2 km/s.

What is the relation between escape velocity and orbital velocity?

vₑ = √2v₀

Report An Error

Exams

Test Series

Previous Year Papers

Syllabus

Books

Cut Off

Latest Updates

Eligibility