Question

The expansion of an ideal gas of mass m at a constant pressure P is given by the straight line D. Then the expansion of the same ideal gas of mass 2m at a pressure P/ 2 is given by the straight line.

• A. (a) E
• B. C
• C. B
• D. A

Answer 1

Answer: (D)

A

Answer 2

$M_{1} = M$, $T_{1} = 60 + 273 = 333K$, $M_{2} = M - \frac{M}{4} = \frac{3M}{4}$ [As 1 / 4^th part of air escapes]

If pressure and volume of gas remains constant then MT

= constant

∴ $\frac{T_{2}}{T_{1}} = \frac{M_{1}}{M_{2}} = \left( \frac{M}{3M/4} \right) = \frac{4}{3}$ ⇒ $T_{2} = \frac{4}{3} \times T_{1} = \frac{4}{3} \times 333 = 444K = 171{^\circ}C$