First law of thermodynamics

In this episode, we delve into the First Law of Thermodynamics, a fundamental principle that governs energy conservation. We explore how energy is transferred in the form of heat and work, and how it relates to a system's internal energy. Building on concepts like temperature and heat from previous episodes, we’ll illustrate the equation of the First Law and its applications in real-world systems, such as engines and refrigerators. This episode is a stepping stone to understanding the Second Law, entropy, and thermodynamic cycles in upcoming discussions.

Check your understanding

These are the same multiple-choice questions you will see in the Quiz section after you listen to the episode. Use them here to preview or review the answers.

What does the First Law of Thermodynamics state?

  1. Energy can be created and destroyed.
  2. Energy is always conserved in a system.
  3. Energy can transfer as heat or work.
  4. Heat is always converted into work.
  5. Work is always greater than heat input.

What is the formula for the First Law of Thermodynamics?

  1. Q = ΔU + W
  2. ΔU = Q - W
  3. W = Q - ΔU
  4. ΔU = W + Q
  5. Q = W/ΔU

In an isothermal process, what is true?

  1. Temperature remains constant.
  2. ΔU = 0.
  3. Work done equals heat added.
  4. No heat is transferred.
  5. Pressure remains constant.

What happens in an adiabatic process?

  1. No heat is exchanged.
  2. Internal energy change equals work done.
  3. Pressure remains constant.
  4. Temperature remains constant.
  5. Volume remains constant.

Which is a real-world application of the First Law of Thermodynamics?

  1. Heat engines converting heat to work.
  2. Refrigerators transferring heat to cooler regions.
  3. Kinetic energy being destroyed in collisions.
  4. Biological systems converting chemical energy to heat and work.
  5. Electric circuits generating heat only.

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