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Chemistry · PYQ NEET UG 2017
हिन्दीA gas is allowed to expand in a well-insulated container against a constant external pressure of \( 2.5 \text{ atm} \) from an initial volume of \( 2.50 \text{ L} \) to a final volume of \( 4.50 \text{ L} \). The change in internal energy \( (\Delta\text{U}) \) of the gas in joules will be
Correct answer · Option 3
\( -505 \text{ J} \)
Explanation
For adiabatic process, \( q = 0 \), hence \( \Delta\text{U} = w = -P_{\text{ext}}\Delta\text{V} = -2.5 \text{ atm} \times (4.50 - 2.50)\text{ L} = -5.0 \text{ L atm} = -5.0 \times 101.3 \text{ J} \approx -506.5 \text{ J} \approx -505 \text{ J} \).
