Question

An amount of n moles of a monatomic ideal gas in a conducting container with a movable piston is placed in a large thermal heat bath at temperature T1 and the gas is allowed to come to equilibrium. After equilibrium is reached, the pressure on the piston is lowered so that the gas expands at constant temperature. The process is continued quasi-statically until the final pressure is 4/3 of the initial pressure p1.

Find the change in the internal energy of the gas.
a) No change in internal energy
b) Positive work done
c) Positive heat absorbed

Answer 1

The change in internal energy of a monatomic ideal gas undergoing a quasi-static expansion at constant temperature is zero.

Step-by-step explanation:

The change in internal energy of a monatomic ideal gas undergoing a quasi-static expansion at constant temperature can be found by considering the first law of thermodynamics, which states that the change in internal energy of a system is equal to the heat added to the system minus the work done by the system. In this case, since the temperature is constant, the change in internal energy is zero, as the internal energy of an ideal gas depends only on its temperature. Therefore, the answer is a) No change in internal energy.