The p-V diagram of a system undergoing thermodynamic transformation is shown is figure. The work done by the system in going from A → B → C is 50 J and 20 cal heat is given to the system. The change in internal a energy between A and C is

Question

The p-V diagram of a system undergoing thermodynamic transformation is shown is figure. The work done by the system in going from A → B → C is 50 J and 20 cal heat is given to the system. The change in internal a energy between A and C is (A) 34 J (B) 70 J (C) 84 J (D) 134 J

Tardigrade Admin · Accepted Answer

From the first law of thermodynamics, if an amount of heat Q is given to a system, a part of it will be used in increasing the internal energy (Δ U) of the system and rest in doing work (W) by the system. Therefore, Q=Δ U+W ⇒ Δ U=Q-W Given, Q=20 cal=20× 4.2J=84 J W=50 J ∴ Δ U=(84-50)J=34 J

Q. The p-V diagram of a system undergoing thermodynamic transformation is shown is figure. The work done by the system in going from A → B → C is 50 J and 20 cal heat is given to the system. The change in internal a energy between A and C is

34 J

70 J

84 J

134 J

From the first law of thermodynamics, if an amount of heat Q is given to a system, a part of it will be used in increasing the internal energy (ΔU) of the system and rest in doing work (W) by the system. Therefore, Q=ΔU+W ⇒ ΔU=Q−W Given, Q=20cal=20×4.2J=84J W=50J ∴ ΔU=(84−50)J=34J

Q. The p-V diagram of a system undergoing thermodynamic transformation is shown is figure. The work done by the system in going from A $\to$ B $\to$ C is 50 J and 20 cal heat is given to the system. The change in internal a energy between A and C is