Thermodynamics Question 16

Question 16 - 31 January - Shift 1

The pressure of a gas changes linearly with volume from $A$ to $B$ as shown in figure. If no heat is supplied to or extracted from the gas then change in the internal energy of the gas will be

(1) $6 J$

(2) Zero

(3) $-4.5 J$

(4) $4.5 J$

Show Answer

Answer: (4)

Solution:

Formula: First law of thermodynamics

As $\Delta q=0$

$\Delta u=-W$

$W=\int PdV$

$\Delta u=-W=30 \times 10^{3} \times 150 \times 10^{-6}$

$=4500 \times 10^{-3}$

$=4.5 J$