# NEET Physics Thermodynamics Questions Solved

In an adiabatic expansion of a gas initial and final temperatures are T1 and T2 respectively, then the change in internal energy of the gas is -

(1) $\frac{R}{\gamma -1}\left({T}_{2}-{T}_{1}\right)$

(2) $\frac{R}{\gamma -1}\left({T}_{1}-{T}_{2}\right)$

(3) R(T1T2)

(4) Zero

(1) $\Delta U=-\Delta W=-\frac{R\left({T}_{1}-{T}_{2}\right)}{\left(\gamma -1\right)}$

$=\frac{R\left({T}_{2}-{T}_{1}\right)}{\gamma -1}$

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