Choose the correct statement for the work done in the expansion and...

Choose the correct statement for the work done in the expansion and heat absorbed or released when 5 litres of an ideal gas at 10 atmospheric pressure isothermally expands into vacuum until volume is 15 litres:

Options

ABoth the heat and work done will be greater than zero
BHeat absorbed will be|less than zero and work done will be positive
CWork done will be zero and heat will also be zero
DWork done will be greater than zero and heat will remain zero

Correct answer

C. Work done will be zero and heat will also be zero

Step-by-step solution

Since it is isothermal,

\Delta \mathrm{T}=0 \Delta

\mathrm{U}=\mathrm{nC}

\mathrm{C}_{\mathrm{v}} \Delta \mathrm{T}=0

Since expansion is taking place against vacuum

P_{\text{ext }}=0 W=-P

\Delta V=0

From first law of thermodynamics,

\Delta U=q+W 0=q+0 q=0

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