First law of thermodynamics- Old is Gold

  1. Air escaping from an air-hose at a gas station always feels cold. Why?
  2. Differentiate between isothermal and adiabatic change.
  3. Why has a gas two values of molar heat capacities?
  4. What is meant by adiabatic expansion? Explain.
  5. Why is Cp greater than Cv?
  6. Why does internal energy remain constant in an isothermal system?
  7. What do you mean by internal energy of a gas?
  8. A cylinder filled with a gas is being carried inside a fast moving train, what change will be there in the internal energy of the gas?
  9. Is internal energy of an ideal gas, the sum of kinetic energy and potential energy at a temperature greater than absolute zero? Explain.
  10. Is it possible to increase temperature of a body without giving heat to it? Explain.
  11. What is the difference between isobaric and isochoric processes? Explain.
  12. What happens to the internal energy of a gas during (i) isothermal expansion (ii) adiabatic expansion?
  13. Milk is poured into a cup of tea and is mixed with spoon. Is this an example of reversible process? Explain.

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