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Question
Give the expression for work done by the gas.
Solution
When a gas expands against pressure, it does work on the surroundings. The work done in expansion for volume V1 to V2 is given by
W = `int_("V"_1)^("V"_2) "PdV"`
If the pressure remains constant during expansion,
Then W = P(V2 – V1) = P∆V
If the volume remains constant, then W = 0.
If there is no external pressure, then no work is done. For example, when a gas expands freely in a vacuum, no work is done by it.
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