Question

The second law of thermodynamics introduced the concept of (1) Third law of thermedynamics (2) Work (3) Entropy (4) Internal energy

Short answer

The second law of thermodynamics introduced the concept of entropy.

Step-by-step solution

Understand the Second Law of Thermodynamics

The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time. This law introduces the concept that entropy tends to increase, leading to a more randomized and disordered state. Recognize that entropy is key here.

Compare Answer Options

Look at the provided options: (1) Third law of thermodynamics, (2) Work, (3) Entropy, (4) Internal energy. Compare each option to the concept introduced by the second law.

Identify the Correct Concept

The second law specifically introduces the concept of entropy. While 'work' and 'internal energy' are related to thermodynamics, they are not the central focus of the second law.

Select the Correct Answer

Since the second law of thermodynamics mainly deals with the concept of entropy, the correct answer is (3) Entropy.

Key concepts

Entropy

Entropy is a fundamental concept in physics, especially in thermodynamics. It measures the amount of disorder or randomness in a system. According to the second law of thermodynamics, the entropy of an isolated system never decreases; it either stays constant or increases. You might think of it like a messy room: without any effort to clean it, the room naturally gets messier over time. This 'messiness' is analogous to increasing entropy. In mathematical terms, entropy can be denoted as \( S \), where S stands for entropy. The more chaotic a system is, the higher its entropy.

Thermodynamics laws

Thermodynamics is governed by four key laws that describe how energy moves within a system.

• The Zeroth law: If two systems are each in thermal equilibrium with a third system, then they are in thermal equilibrium with each other.
• The First law: Also known as the Law of Energy Conservation, it states that energy cannot be created or destroyed, only transformed or transferred.
• The Second law: States that the entropy of an isolated system always tends to increase over time. This law introduces the concept that natural processes have a preferred direction, often towards disorder.
• The Third law: As the temperature of a system approaches absolute zero, the entropy approaches a minimum value (often zero).

Together, these laws form the backbone of modern thermodynamics, explaining how and why energy transfers and transformations occur.

Isolated systems

An isolated system is a physical system with no interaction with its surroundings. This means no energy or matter can enter or leave, making it a perfect environment to apply the second law of thermodynamics. Since no external influence can decrease the entropy in an isolated system, this law easily holds true. Examples of an isolated system are rare in the real world since nearly everything interacts with its environment to some degree. However, an insulated thermos containing hot coffee could be considered an isolated system for practical purposes. Over time, \(dQ = 0\) and \(dW = 0\), where \(dQ \) is the heat transferred and \(dW \) is the work done by the system. However, the entropy within the isolated system can still change, usually increasing towards randomness.