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Question

The first law is broken when a machine operates continuously and breaks one of the following:

The correct answer is PMM1

Understanding the First Law and PMM1

The question asks about a machine that operates continuously and breaks one of the given options, resulting in the violation of the first law of thermodynamics. Let's look at the options provided, which relate to Perpetual Motion Machines (PMMs) and their relation to the laws of thermodynamics.

What is the First Law of Thermodynamics?

The First Law of Thermodynamics is essentially a statement of energy conservation. It says that energy cannot be created or destroyed in an isolated system; it can only be transformed from one form to another. In simpler terms, for any process, the change in the internal energy of a system is equal to the heat added to the system minus the work done by the system. Mathematically, this is often expressed as:

\(\Delta U = Q - W\)

Where:

  • \(\Delta U\) is the change in internal energy of the system.
  • \(Q\) is the heat added to the system.
  • \(W\) is the work done by the system.

A machine that violates this law would either create energy out of nothing or destroy energy, which is not possible according to the first law.

Relating Perpetual Motion Machines to Laws of Thermodynamics

Perpetual Motion Machines are hypothetical machines that would run forever without any external energy source or violate thermodynamic laws in some way. They are often classified based on which law of thermodynamics they would violate:

  • PMM1 (Perpetual Motion Machine of the First Kind): This is a machine that would produce work continuously without consuming an equivalent amount of energy. In essence, it would create energy, which directly violates the First Law of Thermodynamics.
  • PMM2 (Perpetual Motion Machine of the Second Kind): This is a machine that would violate the Second Law of Thermodynamics. This could involve converting heat completely into work in a cyclic process or transferring heat from a colder body to a hotter body without external work.
  • PMM0: This term is sometimes used informally, but it doesn't correspond to a standard type of PMM related to a specific law like PMM1 or PMM2. It might refer to a machine that could operate indefinitely without friction or resistance, but this doesn't necessarily violate a fundamental thermodynamic law itself, but rather implies ideal conditions that are impossible to achieve in reality.

First Law Violation and PMM1

The question states that the machine operates continuously and breaks one of the options, leading to the first law being broken. Based on the definitions:

  • Breaking the First Law means violating the principle of energy conservation.
  • A PMM1 is defined as a machine that produces work without energy input, thereby violating the First Law.
  • A PMM2 violates the Second Law, not the First Law.

Therefore, a machine that operates continuously and breaks the condition related to a PMM1 (i.e., behaves like a PMM1) is the scenario where the First Law of Thermodynamics is broken.

The option that directly corresponds to a violation of the First Law of Thermodynamics is PMM1.

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Important Questions from Statement of First Law of Thermodynamics

  1. Which term of the following is defined by the first law of thermodynamics?

  2. A stationary mass of gas is compressed without friction from an initial state of 0.3 m3 and 0.105 MPa to a final state  of 0.15 m3  and 0.105 MPa, the pressure remaining constant during the process. There is a transfer of 37.6 kJ of heat  from the gas during the process. How much does the internal energy of the gas change?
  3. The first law of thermodynamics is synonymous with the ______.

  4. A system is undergoing a cycle that consists of three processes. During the first process, the work is 5 kJ and the heat is 23 kJ. In the second process no work takes place and the heat interaction is -50 kJ. The third process is adiabatic. The work in the third process is

  5. Which one of the following process is the energy efficient one for compression of air

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