KCET 2025 Physics Paper

According to the first law of thermodynamics, the change in internal energy (∆U) of a system can be expressed as:
∆U=Q−W
Where Q is the heat absorbed by the system and W is the work done by the system.
For paths 1 and 2 from state A to state B, the change in internal energy is the same, regardless of the path taken:
∆U1=∆U2
Therefore, the heat absorbed and work done along the different paths follows the relationship:
Q1−W1=Q2−W2
This equation signifies that the net change in energy (considering both heat and work) is equal for both paths due to the same change in internal energy from state A to state B.