Consider 2 imaginary thermodynamic processes represented in the figure. The path

Question

Consider 2 imaginary thermodynamic processes represented in the figure. The paths share the initial point i and the final point f. Path 1 (yellow) consists of 4 sub processes as follows: an isothermal expansion (work is 50J in magnitude), an adiabatic expansion (work is 40J in magnitude), an isothermal compression (work is 30J in magnitude), and then an adiabatic compression (work is 25J in magnitude). Now, calculate the change in the internal energy throughout the process along path 2 (purple).

Explanation / Answer

Given
path1 (yellow)
isothermal expansion, step 1 -> work = 50 J
   internal energy change in this process = 0 J
   so from first law, heat supplied in this process = work done = 50 J
adiabatic expansino, step 2 -> work = 40 J
   heat supplied = 0 J
   Internal energy change = -40 J ( from first law)
isothermal compression, step 3-> work = work = -30 J
   internal energy change = 0 J
   so from first law, heat supplied in this process = work done = -30 J
adiabatic comperssion, step 4 -> work = -25 J
   heat supplied = 0 J
   Internal energy change = 25 J
NEt work sone by the system = 40 + 50 - 30 - 25 = 90 - 55 = 35 J
now internal energy change along path 1 = 0 - 40 + 0 + 25 = -15 J
but the first and the second p[aths share the initial and the final points
and internal energy is a state ariable and does not depend on the path but only on the initial and the final points
so, net internal energy change in path 2 = -15J

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.