An ideal gas expands in volume from $1 \times 10^{-3} \mathrm{~m}^{3}$ to $1 \times 10^{-2} \mathrm{~m}^{3}$ at 300 K against a constant pressure of $1 \times 10^{5} \mathrm{Nm}^{-2}$. The work done is

JEE Main · 2004 · 24 Apr 2004 · Offline · Chemical Thermodynamics

An ideal gas expands in volume from

1 \times 1 0^{- 3} m^{3}

1 \times 1 0^{- 2} m^{3}

at 300 K against a constant pressure of

1 \times 1 0^{5} Nm^{- 2}

. The work done is

Answer: (A)

Work done against a constant external pressure is

W = - P_{e x t} Δ V

. The gas expands from

1 \times 1 0^{- 3} m^{3}

1 \times 1 0^{- 2} m^{3}

, a change of

Δ V = 9 \times 1 0^{- 3} m^{3}

, against

1 \times 1 0^{5} N m^{- 2}

. So

W = - (1 \times 1 0^{5}) (9 \times 1 0^{- 3}) = - 900 J

, the negative sign showing the gas does work on its surroundings as it expands.

JEE Main · 2004 · 24 Apr 2004 · Offline · Single correct option