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Chemistry · THERMODYNAMICS
हिन्दीA system undergoes an adiabatic process where \( 1.5\text{ kJ} \) of work is done by the system. In another step, an electrical work of \( 500\text{ J} \) is done on the same system while it absorbs \( 800\text{ J} \) of heat. The net change in the internal energy of the system across the entire two-step process is:
Correct answer · Option 2
\( -200\text{ J} \)
Explanation
Step 1: Adiabatic, so \( q_1 = 0 \), \( w_1 = -1500\text{ J} \) (work done by system) \( \implies \Delta U_1 = -1500\text{ J} \). Step 2: \( q_2 = +800\text{ J} \), \( w_2 = +500\text{ J} \) \( \implies \Delta U_2 = 800 + 500 = +1300\text{ J} \). Total \( \Delta U = \Delta U_1 + \Delta U_2 = -1500 + 1300 = -200\text{ J} \).
