Question

For the monoatomic ideal gas shown in the given P-V diagram. Choose the correct statements.

• A. The internal energy decreases during 3 - 4
• B. The work done by the gas is positive during 2 - 3
• C. The temperature of the gas decreases during 4 - 1
• D. Work is done on the gas during 1 2

Answer 1

Answer: (A), (C), (D)

The correct options are
A The temperature of the gas decreases during 4 - 1
C The internal energy decreases during 3 - 4
D Work is done on the gas during 1 2

During 3-4,
The body undergoes adiabatic expansion.
Using first law $q=\Delta U+W=0$
$W>0,hence\Delta U<0$.

During 2-3,
Process is isochoric (constant volume).
$W=0$.

During 4-1,
Process is isochoric,
Hence if follows the law $P\propto T$
Since, $dP<0,sodT<0$.

During 1-2,
$dV<0⟹W<0$ Hence work is done on the gas.
Options A,C,D are correct.